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Orders. Ostrapodes. Cladocères. Phyllopodes. Copépodes. Laemipodes. Isopodes. Amphipodes. Stomapodes. Decapodes. M. Milne Edwards further states that Latreille, a little before his death, was again occupied with the subject, and introduced into his method many modifications, which made it approach nearly to that proposed by M. Milne Edwards. The latter says that Latreille in fact admitted into the class Crustacea 12 orders, viz., the Decapods, the Stomapods, the Laemipods, the Amphipods, the Isopods, the Dicladopods, the Lophyropes, the Ostrapods, the Xyphosures, and the Siphonostomes; and that the Dicladopods very nearly corre: spond to the Copepods of M. Milne Edwards. The last-named author, when speaking of Latreille's classification in the first edition of the “Régne Animal, speaks of Latreille's not attaching to the distinction of Malacostraca and Entomostraca an importance which those divisions do not deserve; but M. Milne Edwards still retains the term Entomostraca; for we find in his synoptical table (Histoire Naturelle des Crustacés—Suites d Buffon), under the subclass of Maarillated Crustaceans, the legion of Branchiopods, containing the orders Ostrapoda and Phyllopoda, and the legion of Entomostraca, consisting of the orders Copepoda and Cladocera. The reader who wishes to study the classification, economy, and anatomy of the Entomostraca, should more particularly consult, besides the works above alluded to, those of Swammerdam, Needham, Leuwenhoek, De Geer, Ramdhor, Schoeffer, Straus, Hermann, the younger Fabricius, the Jurines, father and son, Adolphe Brongniart, Slabber, Desmarest, De Blainville, Thompson, and Audouin. ENTOZO'A (from the Greek words entos (i.vröc), within, and zóon (ojov) an animal). Under this name are designated the different living beings which are produced and developed within other living beings. It comprehends a series of animals differing greatly from one another in form and organization, and having but one character in common; which is, that they are all parasitic, or have their exclusive habitation in, and live at the expense of the bodies of other animals. They can scarcely be said to form a distinct class in the animal kingdom, some of the species being closely resembled both in external appearances and internal structure, by individuals placed in other classes, and only differing from them in the localities where they are found; thus the zoosperms, or seminal animalcules, which are enumerated by some zoologists with the entozoa, closely resemble the true cercariae of vegetable infusions. Entozoa are found in most animals; they have been discovered in all the mammalia from man down to the cetacea; they also occur in the other classes of the vertebrata; indeed, it seems that a greater number reside in birds, reptiles, and fishes than in mammals. The invertebrata have also their peculiar parasites; and they have been ascertained to exist in all the insect tribes, and in beings still lower in the scale. The best known species are those which inhabit the intestines of the human subject, and vulgarly go by the denomination of worms, which term was probably derived from the resemblance which the Ascaris lumbricoides bears to the common earth-worm, as this species is most frequently met with, and was the first described of the human entozoa, being mentioned by Hippocrates, who called it the Apulic orpo)75Xoc, or round worm. A short list of the different kinds of worms found in the human intestinal canal, with an enumeration of their causes, the morbid symptoms which they occasion, and the mode of treatment, are given under the article ANTHELMINTICs. With regard to the causes of the formation, or the primary origin of the entozoa, nothing is known; and the whole subject is entirely involved in darkness; they must either be supposed to be the product of spontaneous generation, or the germs of them are introduced from without. Many arguments have been adduced on both sides of the question, but as the discussion would lead to no useful results, we shall leave it untouched, and proceed to give a short sketch of these curious and interesting animals.

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According to the derivation of the word Entozoa, and the definition which we have given of it, this term should include every living creature found in the body of another (which has not i. introduced from without): thereföre the small microscopic animalcules detected in the semen of animals, called Spermatozoa, come under this head; and in a very able paper on the entozoa by Mr. Owen, we find them placed accordingly in this class, only situated in a separate group, denominated Protelmintha, and divided from the animals forming the class entozoa of Rudolphi. These minute beings, which, from their size and organization, rank with the assemblage of animalcules which are collected under the head Infusoria in the “Régne Animal,” have been detected in the secretion of the testicles of various mammiferous animals arrived at *. When a drop of the secretion is expressed from a divided was deferens shortly after death, and examined with a microscope, after being diluted with water, it is seen to be filled with minute beings resembling tadpoles, and swimming about in various directions, with different degrees of velocity, guided by the inflection of a slender tail. It has been doubted whether these are animated beings at all, or are to be considered as analogous to the moving filaments of the pollen of plants; but leaving this undecided, we may proceed to state that the body is always of a compressed form, which will distinguish these animalcules from the vegetable infusoria, in which the body is always ovoid or rounded. With regard to their organization, no alimentary canal or gastric cavities have been detected, nor organs of generation; they are said to be fissiparous, the body and tail spontaneously dividing, and forming two independent beings. The shape of these zoosperms differs in different animals, the large end, or body, being bigger in proportion to the tail in some than in others, and their size not being always in relation to that of the animal to which they belong: thus those of the rabbit are nearly as large as those from the bull. That these animalcules perform some office in the economy of nature seems probable from the fact that in those animals which are subject to periodical sexual development, as the hedgehog and mole (in which the testes undergo an alteration in size in different seasons), these creatures are not found during the period of quiescence, or partial atrophy of the glands; neither do they exist in the seminal passages before the age of puberty. But the part in the physiology of generation which these zoosperms perform is not so clear. The spermatozoa have been detected in the other orders of the vertebrate and in the articulate animals,

In the present group are also included those minute internal parasites which have been detected in the bodies of many of the entozoa themselves, and which, from their external form, are referrible to the infusoria.

The Trichina Spiralis, an entozoon, found inhabiting the muscles of the human subject, has been placed by Mr. Owen, who first described it, with the preceding animalcules; but further observations on its organization have discovered a complexity of structure which qualifies it to occupy a place in the highest instead of the lowest group into which the present class of animals is divided.

We now proceed to the more legitimate part of our subject, viz. the true parasites forming the class Entozoa of Rudolphi, and it is first necessary to arrange them according to some classification. Availing himself of the difference in their internal organization, Cuvier divided them into the “cavitaires,” or those which have an abdominal cavity, and a distinct intestinal canal within it, and the ‘parenchymateux,” or those in which no intestinal tube is traceable, and which for the most part cousist throughout of an homogeneous structure; but this classification is any thing but a natural one, as worms the most dissimilar in their general appearance are here promiscuously congregated together. Mr. Owen, in the article which we have before alluded to (in the Cyclopaed, of Anat.), has adopted the arrangement of Cuvier, only inventing new Latin names derived from the Greek, instead of the French terms: thus he denominates the ‘parenchymateux' 'sterelmintha, from elmins, ‘a worm, and stereos, “solid;' and the ‘cavitaires’ ‘ coelelmintha, from elmins, and coelos, “hollow.” Zeder laid the first foundation of a good classification of these animals, dividing them into five classes, afterwards called families, at Rudolphi's suggestion; and these were again subdivided into genera and species. Rudolphi himself doubted the possibility of ever reducing all the species of entozoa to absolutely natural and well-defined families, but as Zeder's system seemed the most perfect, he has adopted it for his own; and it does not seem that we can do better than follow the arrangement of this great entozoologist in the present article. According to this classification the entozoa are divided into five orders, or families, the Nematoidea, Acanthocephala, Trematoda, Cestoidea, and Cystica. The only point in which we shall depart from this arrangement will be, that, instead of commencing with the most perfect, and descending to the most simple, we shall begin with the lowest in the scale of organization, and ascend to those possessing the most complicated structure, as this is most in accordance with the laws of the animal kingdom. Order I. is Cystica (from cystes (kāoric) a bladder) hydatids: the characters are:—body flattish, or roundish, and terminating posteriorly in a transparent cyst filled with pellucid fluid, which is sometimes common to many individuals; the head is retractile, and provided with pits two or four in number, or four suckers and a circle of hooklets, or with four unarmed or uncinated tentacles. The organs of generation and nutrition are unknown. This is not a very natural family, the species being closely allied to those of the next order in the structure of the heads and the Ecchinococcus, or granular hydatid, though referred to it, is not hollow. Order II. Cestoidea (from cestos (ksaröc), ‘a band;’ and eidos (tiôoc), “form), tape-worms. Characters:–body elongated, flattened, soft, continuous, or articulated, furnished with lateral or marginal pores, and erectile papillae passing through them, supposed to be the male organs of generation. Head generally provided with two or four pits, or suctorial

orifices, and sometimes with four retractile, unarmed, or un

cinated tentacles; but the head is so dissimilar in different genera, and their shape varies so much, that they do not form a very natural family. There is no trace of intestinal canal; unless the vessels proceeding from the suckers be considered as such. In some species nutrient vessels and ovaries are to be seen. They are all androgynous. Order III. Trematoda (from trema (rpiina), ‘a foramen’), fluke-worms. Characters :—body soft, rounded, or flattened. Head indistinct, with a suctorial foramen ; one or more suctorial pores on the under surface of the body, which furnish the grounds for their subdivision into genera: they have no intestinal canal, and the organs of generation of the two sexes co-exist in the same individual: this is a very natural order. Order IV. Acanthocephala (from acantha (drav0a), “a thorn; and céphale (repax)), ‘the head), hooked-worms. Characters:—body elongated, round, subelastic ; the anterior extremity or head has a retractile proboscis, furnished with hooks or spicula, arranged in rows. They have no intestinal canal, but distinct genital organs, and a separa*tion of the sexes. This is a very natural group, and includes the most noxious of the internal parasites: there is only one genus, and fortunately no species is known to infect the human body. Order V. Nematoidea (from nema (vijua), “a thread,' and eidos, “form'), round-worms. Characters:—body cylindrical, eiongated, and elastic; structure very complicated, there being a true intestinal canal, terminated by a distinct anus. The mouth, by its varieties, affords generic characters; the sexes are distinct; the females, which are longer than the males, being for the most part oviparous: they constitute a very natural order. Having given the above brief view of the orders into which the class Entozoa is divided, with the leading or characteristic differences in their form and organization, we will now enumerate the principal genera contained in each group, and make a few observations on some of the most interesting species. Following the order of classification, we must commence with the most simple group, the Cystica; and here the first parasite which attracts our attention is the common hydatid, which consists of a globular bag, composed of condensed albuminous matter of a laminated texture, and contains a limpid colourless fluid. No head or appendices of any sort being attached to it, it is appropriately denominated an acephalocyst, that is, a headless cyst. This genus was established by Linnaeus, who regarded as animals those productions which before his time had been considered simply as cysts. Considerable diversity of opinion still exists as to their nature, and it is impossible to determine whether an hydatid is an animal or not, till we can agree what is the definition of an animal; if an animal must have sensation and motion, this is not one, as the best observers

agree that the acephalocyst is impassive under the application of stimuli of any kind, and manifests no contractile power, either partial or general. If an animal is characterized, on the other hand, by independent existence merely, the hydatid is one; and as such we shall regard it, for it is certainly an independent organized being, growing by intrinsic power of imbibition, and reproducing its species by gemmation: the young are developed between the layers of the parent cyst, and thrown off internally or externally, according to the species. It is a being certainly far inferior in the scale to the Cysticercus, but still not the less an independent creature. Its structure is very similiar to that of some of the lowest forms of algae in the vegetable kingdom, as the protococcus nivalis or red snow of the arctic regions, which consists of simple and minute vesicles, which propagate their kind by gemmules developed from the external surface of the parent. Acephalocysts have been found in almost every structure and cavity of the human body, but particularly in the liver, uterus, kidneys, and cellular tissue. The species which resides in man is called A. endogena, the pillbox hydatid of Hunter, from the gemmules being detached from the internal surface of the cyst; and it is thus distinguished from those of the ox and other ruminating animals, which are exogenous, or have the gemmules excluded from the external surface. 2. The next genus is Ecchinococcus, which, as the namo implies, is a round body covered with asperities. The E homunis, or many-headed hydatid of the Germans, occurs in cysts in the liver, spleen, omentum, and mesentery: the cyst, which is externally yellow and coriaceous, is unprovided with head or mouth, and contains minute bodies, which are described as possessing the armed and suctorious head characteristic of the Coenuri and Cysticerci. From observations made on another species, the E. veterinorum, found in animals, the particles adhering to the internal surface of the cyst being examined with a microscope, appeared to be minute animalcules, moving about by means of external vibratile cilia, having an orifice at each extremity of the body, and the centre occupied by large globular stomachs. From this structure these parasites ought to be classed with the Polygastric Infusoria. 3. Anthocephalus is the next genus. It occurs in fish, in the liver, mesentery, and peritoneum, and within hydatids in the viscera. Each animal exists solitarily in a double bladder, of which the outer layer is hard and elastic, the inner more thin and delicate. The body is long, flat, terminated behind by a caudal vesicle, and in front by a head with two or four fossae, and four probosces furnished with spicular processes. 4. Caenurus. This has the terminal cyst common to many bodies and heads; the former are elongated, flattish, and wrinkled; the latter are furnished with a rostrum, on which there are hooks and suckers, adhering in greater or less number to the surface of a bladder filled with fluid. The best known species is the Caenurus cerebralis, commonly developed in the brain of sheep, and giving rise to the disease called the staggers. 5. Cysticercus. Here there is a dilated cyst forming the termination of a single entozoon: the head has four suckers, and a rostrum furnished with recurved processes or hooks. Of this genus one species is known to infest the human subject, the C. cellulosae : it is developed in the interfascicular cellular tissue of the muscles, and is invariably surrounded by an adventitious capsule of condensed surrounding substance. This entozoon occurs much more rarely in this country than on the continent; it is not confined to the muscular structures, for several individuals have been detected in the anterior chamber of the eye, where they may occasion so much irritation and inflammation of the organ as to require extraction, which occurred in a recent case in the Glasgow Ophthalmic Infirmary. These parasites also occur in quadrupeds, particularly the hog, giving rise to that state of the muscles which is called ‘measly pork.’ Of the Cestoid order of Entozoa, Rudolphi has described eight genera, two only of which contain each a single species that infest the human body: 1. Bothriocephalus, the species of which occur frequently in fishes and birds, in the branchiae, oesophagus, pyloric appendices, intestines, and abdominal cavity. The one which affects the human subject, B. latus, or Taenia lata, rarely falls under the observation of the English entozoologist, but is common in the intestines of man in Switzerland, Russia, parts of France, &c. It may be distinguished from the

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Taenia solium by the form of the segments, which are broader than they are long, and by the position of the genital pores, which are on the under surface of the body, instead of at the sides; the head is also very different, for, instead of having four round oscula, characteristic of the true toniae, there are two lateral longitudinal fossae, or bothria. 2. Tania. This genus has the body flat, long, articulated, with four suckers on the head; it occurs in the intestines, billary ducts, gall-bladder, and liver of vertebrate animals. The T. solium, common tape-worm, inhabits the human intestines, but not with equal frequency in all countries, though its distribution seems to be much more extensive than that of the Bothriocephalus latus. It occurs in England, Holland, Germany, Sweden, Italy, Greece, and most countries in Europe, and also in Egypt and the East; and in all these situations the other genus is comparatively rare. The delicacy of their structure, and their so seldom being obtained entire, has thrown great obstacles in the way of their investigation. The head was for a long while unknown, and it was disputed whether nourishment was taken in by the lateral pores of the several joints, or by the mouth alone. Rudolphi says the latter, and it seems now pretty clearly determined that the former are mere outlets of the generative organs. The length to which the T. solium is capable of attaining is very considerable, but quite indefinite. Those passed now-a-days seldom exceed twenty feet, but in former times we read of much more gigantic specimens; but whatever may be thought of some of the accounts which are quite improbable, it indubitably has occa: sionally attained a very great length, having been found extending from the pylorus to within a few inches of the anus, and then by no means fully stretched out. Such cases are however very rare. - The determination of the species in this genus is very difficult: they may be divided for greater convenience into three sections: The first are without a proboscis, the Tania inermes; the second have one, but unarmed, T. rostellatae; the third are furnished with an uncinated proboscis, T. armata”. 3. Caryophyllarus has the body, flat, continuous; the head dilated, and divided into flattish processes; it is furnished with an upper and under lip; the species of this genus occur in the intestines of fishes (carp, &c.). 4. Scolea. The body is flat and continuous; the head has four fossae on it; it occurs also in the intestines and abdomen of fishes, sepia, &c. 5. Gymnorhynchus. This genus has the body very long, with a globular receptacle at the neck; head with two opposite fossae, and four naked retractile probosces; the species occur in the muscular substance of many fish. 6. Tetrarhynchus. Body flat, continuous, head with four fossae and four retractile probosces, furnished with recurvated spicular processes; it occurs in reptiles, fishes, molluscae, in the muscles, branchiae, stomach and its membranes, the liver, and peritoneum. 7. Ligula. In its first stage of development the body is elongated with a longitudinal fissure, without any appearance of head, or organs of generation. In its perfect state there is a simple fossa on each side of the head, and the ovaries and processes form a single or double row along the median line. The speeies occur very frequently in birds and fishes, but very rarely in mammalia. 8. Triaenophorus has the body elongated, flat, sub-articulated, mouth bilabiate, and furnished on each side with two tricuspid acicular processes; it is found in fishes. The Trematode order is divided into six genera, which also include only two species infesting the human body. 1. The first genus is Monostoma, which has only a single anterior pore: it occurs in mammalia, birds, reptiles, and fishes. 2. Amphistoma is furnished with two pores, one anterior and one posterior. Found in the stomach, intestines, and abdomen, and in the hydatids of the viscera of mammals, birds, and reptiles. 3. Distoma. In this genus there are two pores: an anterior and a ventral. An immense number of species are known, occurring in mammalia, birds, fishes, &c., The D. hepaticum, or fluke-worm, frequents the gall-bladder and ducts very frequently in some animals, as the ruminating, and is particularly common in the sheep in the disease called the rot. It has been discovered in the gall-bladder of the human subject, though very rarely. It bears a considerable

resemblance in its shape to a melon-seed, being flat, and appearing lanceolate at each end, as seen with the naked eye, though, when magnified, the extremities are found to be obtuse, the tail being the broader of the two. The anterior pore, or true oš. is round and small; the posterior cavity is imperforate, and only subservient to adhesion and locomotion; it is situated in the ventral aspect of the body, in the anterior half. Between these there is a third orifice, destined to the generative system, and from which a small cylindrical process is generally protruded. The fluke is hermaphrodite and oviparous: it lives upon the bile, which is absorbed by the mouth, and is at once so digested or modified by the vessels which go off from thence, as to become immediately fitting nourishment for the animal. 4. Tristoma has three pores, the anterior simple, and the posterior radiated: it is found in the gills of one or two species of fish. 5. Pentastoma. The mouth is here situated between two pores on each side, through which a spicular process comes out. It occurs in the frontal sinuses, lungs, and surface of the liver of the mammalia (dog, horse, wolf), and in reptiles. 6. Polystoma. This o six anterior pores, besides a ventral and posterior one. It mostly occurs in the throat and branchiae of fishes, and the bladder of frogs; but one species, the P. pinguicola, was discovered by Treutler in the cavity of an indurated adipose tubercle, in the left ovarium of a female aged 20, who had died in child-bed. The tumour, which was apparently formed entirely of indurated fat, was of ... colour and hollow within ; the cavity was nearly filled by the above-named worm, which was about half-an-inch in length, and between one and two lines in width. The 4th order, Acanthocephala, contains but one genus, Echinorhyncus, to which {.. numerous species occurring in all classes of vertebrate animals except man: they are generally found in the intestinal canal, fixed between its membranes, and occasionally even in the peritoneal cavity; they have also been found in the neck under the skin. We now come to the last and most highly organized group of the entozoa, the Nematoidea, which contains a reater number of genera, and includes more species inhabiting the human body than any of the preceding. It has been divided into 11 genera, viz. 1. Filaria; these are of nearly equal thickness throughout their whole length; they occur in all parts of the vertebrata, though principally in the cellular membrane; they are also even found in insects and their larvae. 2. Trichosoma. On its anterior extremity, which is very thin, is the mouth, resembling a minute point: it is found in mammalia, birds, and amphibia, between the coats of the stomach, in the intestines, and the urinary bladder. 3. Trichocephalus. This genus differs from Filaria in the capillary form of the anterior part of the body, and in its swelling out behind; it occurs principally in the caecum of the mammalia. 4. Oryuris is characterized by being subulate posteriorly, having the mouth orbicular, and the penis in a sheath. The Ascaris vermicularis is included in this genus by Bremser. 5. Cucullanus is attenuated posteriorly. It occurs in the intestines and abdomen of reptiles and fishes. 6. Spiroptera is attenuated at each end. It occurs under the nictitating membrane of birds, in various parts of fish, and is said to have been found in the urinary bladder of man. 7. Physaloptera is attenuated at both extremities; the tail of the male is bent downwards, winged, and furnished below with a sort of bladder. The species are found in the stomach of mammalia, birds, and reptiles. 8. Strongylus. This has both ends attenuated: the tail of the male terminates in what Rudolphi calls a bursa, and through this the penis passes out; it occurs frequently in various situations in the three first classes of vertebrate animals. 9. Ascarts. This genus, which is the most numerous of the intestinal worms, 80 species having been already described, has the extremities attenuated, the mouth furnished with three valves or tubercles, and the penis double. The species occur in almost every part of the bodies of vertebrate animals. 10. Ophiostoma is attenuated at the extremities, and has the mouth furnished with two lips. It is found in the intestines of mammalia and fishes.

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- o bodies varied in length from four to eight inches. * the latter substances and ova are preserved in the Museum * * fo

:11. Lizhynchus nas the mouth at the end of a sort of erectile and polished tube. It occurs in the stomach and intestines of some of the mammalia and of many fishes. In the above list of the genera of the cavitary, intestinal, or round worms, we have not made any particular mention of the species parasitic in man, and as several of them possess considerable interest, we need no apology for giving a short description of them. We may begin with the genus Filaria, three species of which are enumerated as human inhabitants, though two of them have been only once detected. The Guinea Worm (Filaria Medinensis) frequently occurs in hot climates, but the countries where it most abounds are Arabia, Upper Egypt, Abyssinia, and Guinea. Its general habitation is the subcutaneous cellular tissue, particularly of the lower extremities; but it is also found in the scrotum, and very rarely beneath the tunica conjunctiva of the eye. The length of this worm varies from six inches to twelve feet: it is about as thick as the string of a violin. Its colour is generally white, but occasionally brown; it is round, and of nearly equal dimensions in its whole length, but becomes a little attenuated towards the anterior extremity. The tail of the male is obtuse, and armed with a spiculum; in the female it is acute and bent. The mode of development of this entozoon is unknown. It seems that it may exist for many months without being detected, cases occurring where it has not been discovered till more than a twelvemonth after leaving the country where it was contracted. After a time it produces irritation; in some É. of the skin a vesicle, pustule, or small abscess forms, reaks, and then the end of the worm makes its appearance, which may be taken hold of, and cautiously and gradually extracted. If the filaria is broken, the portion remaining beneath the skin dies, and produces inflammation, sinuous abscesses, and often great constitutional disturbance, requiring amputation of the limb. It seems to be capable of slowly shifting its situation in the cellular membrane. According to Rudolphi, its coming out through the skin is not to be attributed to perforation of that membrane, which it is not at all capable of effecting, but only to the irritation which it excites in approaching the integuments. It seems sometimes to affect people within the tropics in an endemic or even epidemic form, nearly half the men in a regiment having been attacked at the same time by it. This species has been mentioned as having been found occasionally beneath the conjunctiva of the eye; but another, and much smaller kind, has been detected within the eyeball itself, viz. the Filaria oculi humani, which Nordman met with in the liquor Morgagnii of the capsule of the crystalline lens of a man who had had the operation of extraction for cataract performed. Two minute worms were discovered coiled up together. This species differs from the large Filaria found in the eye of the horse. The third species is the F. bronchialis, which was once detected in the enlarged bronchial glands of a man by Treutler; its length was about an inch. The Trichocephalus dispar, or long thread-worm, is about an inch and a half or two inches in length, the male being smaller than the female. The capillary portion makes about two-thirds of the whole length of this species. This worm is very common in the calcum and large intestines, but does not seem to occasion any inconvenience, though inflammation of the intestinal follicles and fever has been erroneously ascribed to it. The existence and history of the following entozoon are involved in a good deal of mystery. Spiroptera homimis is the name given to some small intestinal worms which were sent to Rudolphi, together with some other vermiform bodies of an elongated form and solid homogeneous texture, which were passed from the bladder of a poor woman still living in St. §o work-house, London. There were also discharged, together with these substances, numerous small granular bodies, considered by Rudolphi as mere morbid concretions, but which subsequent examinations have caused to be regarded as ova. The small nematoid worms, which were six in number, and of different sexes, are supposed to have been expelled from the woman at the same time; they were from eight to ten lines in length, slender, white, and elastic; the other elongated Some of

of the College of Surgeons; but none of the former entozoa, denominated Spiroptera hominis, are to be found among

, them. - The Strongylus gigas also inhabits the urinary apparatus.

Before Rudolphi's time it was generally confounded with the Ascaris lumbricoides, to which it bears some resemblance. It occurs, though rarely, in the substance of the kidneys, where it sometimes attains on enormous size, having been met with three feet long, and half an inch in diameter. The more ordinary dimensions however are about fifteen inches in length and two lines in thickness. The common colour is blood-red, arising from the nature of their food, 'as they obtain their nourishment from the contents of the renal vessels: they occasionally find their way into the bladder, and are discharged with the urine. This entozoon occurs much more frequently in some animals, as the dog, horse, &c., than in man. Their presence in the kidneys does not seem to give rise to any peculiar symptoms differing from those of other renal diseases, The Ascaris lumbricoides, the common round worm so frequently met with in children, is so well known as to require a very brief notice here. It occurs in the hog and the ox, as well as in man, and chiefly inhabits the small intestines. The male is smaller than the female, and much more rare; it may be distinguished by the end of the tail being curved, and terminating in an obtuse point, at the apex of which a small black speck may be frequently observed. In the female this extremity is straighter and thicker. The anus is situated close to the tail in both sexes. In the female there is generally a constriction in the centre of the body where the organs of generation are placed. This worm, when minutely examined, will be found to consist of integuments, muscles, digestive organs, genital apparatus, and a nervous system consisting of an oesophageal ring and a dorsal and ventral cord. It has been supposed to feed on the chyle or mucus in the intestines, and to adhere to the coats of the bowels, but on these points there is considerable doubt. They are often found in great numbers. The last human species in this group is the Ascaris vermicularis, the maw-worm, thread-worm, or ascarides. It is very minute, the male seldom exceeding two lines, and the females five lines in length, and being proportionally slender. Their colour is white; they are so small that there is great difficulty in detecting their structure, but Rudolphi says that he has repeatedly observed the three tubercles round the mouth characteristic of the genus. Their abode is the large intestines, particularly the rectum, where they sometimes occur in immense numbers, and occasion great irritation. We have now enumerated all the genera of Entozoa described by Rudolphi and other Entozoologists, but before we conclude our subject we will say a few words on the Trichina spiralis which we have before mentioned. It is a microscopic parasite, infesting the muscles of the human subject, belonging to the voluntary class, and found in greater numbers in those that are superficial than in the deep seated. Their nidus seems to be in the interfascicular cellular tissue. A portion of muscle affected by these animals appears beset with whitish specks, which, if examined with a microscope, are found to be little cysts containing a minute worm coiled up. The cysts are of an elliptical shape, and attenuated towards the extremities their length is about oth of an inch, and breadth oth. By cutting off one extremity of the cyst, the trichina may be extracted entire, when it is generally found rolled up in two or two and a half spiral coils. Being straightened out, it will be found to measure oth of an inch in length and oth of an inch in diameter. From the minuteness of the object, it is necessary to employ a magnifying power of considerable intensity to examine it satisfactorily, and from the difficulty of managing the investigation, and the deceptive appearances produced under the microscope, it is not easy to detect its organization. Mr. Owen never succeeded in discovering an intestinal tube, or cavity, and therefore, as we have stated, placed this entozoon in his first group along with the seminal animalcules. (See Zool. Trans, vol. i. ; and Zool. Proceedings, Feb. 1835.) Dr. Arthur Farre observed by very patient and minute observation with the microscope, under favourable circumstances, that it possesses an intestinal canal with distinct parietes, (Med. Gazette, Dec. 1835), and upon this ground it ought to occupy a higher station among the nematoid or intestinal worms; but further researches are necessary, before it can be stated with confidence in which, group this entozoon should be Fo It seems that this parasitical affection of the uman body is unconnected with age, sex, or any particular form of disease, and it appears that it may exist without giving rise to any debility of the vital powers, or even with

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out interfering with the enjoyment of robust health, as has been shown in a case lately met with. All the known parasites residing within the human body have now been mentioned, and we have given a general outline of the groups and genera of the class Entozoa. It would far exceed our limits to attempt to enumerate all the species which have been discovered, and described by authors; which would even then probably include but a small number of those which exist. In fact, if we assent to the theory of their being the product of some irregular process of nutrition or secretion within animal bodies, or, as it is called, spontaneous or equivocal generation (which is perhaps more probable than that they are introduced from without), new and dissimilar species may be formed every day, by some unknown modification of the nutritive process which gives birth to them. The laws which, according to this hypothesis, regulate the difference of structure in these beings, from the simple acephalocyst to the complicated ascaris, are as much involved in obscurity as those which cause the varieties of organization in morbid productions connected with and participating in the life of the rest of the body; for instance, the various classes of tumours. ENTRE DOURO E MINHO, a province of Portugal, bounded on the north by the river Minho, which separates it from Gallicia in Spain, and on the south by the Douro, which divides it from the province of Beira. From its *. tion between these two rivers the province has derived its name, although it is sometimes also called the province of the Minho, for brevity's sake. To the east it is bounded by the province of Tras Os Montes, and to the west by the Arlantic Ocean. Its length is about 60 miles from north to south, and its breadth is about 40 miles. Its area is, according to Miñano, 240 square leagues, of 20 to 1 degree of latitude, or about 2880 English square miles. Its population, by the same authority, as well as that of Antillon, is about 900,000, which is nearly one-fourth of the whole pobulation of Portugal, it being by far the most thickly inha!. province of that kingdom. It is divided into five comarcas, or districts, namely, Braga, Viana, Penafiel, Guimarães, and Oporto. The principal towns are, Braga, the capital of the northern division of the province [BRAGA]; Porto or Oporto, the capital of the southern division, by far the most important town in it [OPoRto]; Guimarães, on the river Ave, an antient town, once the cradle and the capital of the monarchy, at present an industrious busy place, with manufactures of linen, leather, and cutlery, and 6000 inhabitants; Viana, with 8000 inhabitants, and a harbour at the mouth of the Lima, carrying on a considerable trade; Villa do Conde, with a small harbour, and 3000 inhabitants; Barcelos, with 3900; Valença, on the Minho, a frontier town and fortress, with about 1600 inhabitants; Tenafiel, with 2300; Caminha, at the mouth of the Minho, with a harbour, and about 1000 inhabitants; S. João da Foz, at the mouth of the Douro, below Oporto, with 3300 inhabitants; Amarante, on the Tamega, with about 1000 inhabitants. The surface of the province is hilly, but there are some plains near the sea-coast. One ridge of mountains, the Serra de Marão, runs from north to south through the east part of the province, near the borders of Tras Os Montes; the rivers Cavado, Ave, and Neiva have their sources in these mountains. The river Lima, which, next to the Douro and the Minho, is the largest in the country, ‘has its source in the mountains of Gallicia; it enters the province of Entre Douro e Minho at its north-east extremity near Lindoso, runs through the north part of the province, passes by Ponte de Lima, and enters the sea near Wiana. The river Tamega, which has its source in Tras Os Montes, flows through the province of Entre Douro e Minho in a southern direction, passes by Amarante and Canavezes, ..and then enters the Douro. This province is the most fertile in Portugal, the climate is healthy, and the soil is irrigated by numerous streams. The principal productions are wine, oil, flax, Indian corn, some wheat and oats, and vegetables and fruits of all sorts. Pastures are rather scarce, yet a considerable quantity of cattle, both large and small, are reared. The principal article of exportation is wine, which is made chiefly from the vineyards which are planted all along the valley of the Douro, and which is ... at Oporto under the name of port-wine. There are fisheries along the coast, which occupy a great number of hands. The natives of Bntre Douro e Minho are considered, together with their neighbours of Tras Os Montes, as the finest race of men in

Portugal: they are industrious, civil to strangers, and or. derly. The province is divided into two administrative divisions, Braga and Oporto, called also Alto Minho and Baixo Minho, each having its military and civil governors and its courts of justice. The division of Alto Minho includes Braga and Viana, and all the northern part of the country from Braga to the Minho; that of Baixo Minho, which is by far the larger, includes Oporto, Guimaraes, Penafiel, Amarante, and all the country southwards as far as the Douro. ENTRESOL, a French term used to signify a floor be. tween other floors. The entresol consists of a low apartment or apartments, usually placed above the first floor. In street architecture it is desirable to form the basement story on a scale of grandeur, and in so doing a greater space than necessary would be given to the first floor, if it were not for the entresol. There is a very good example of an entresol under the colonnade of the Quadrant in London. In continental i. the entresol is frequently employed, especially in arls. The term Mezzaninro (or little middle floor) is used in Italy to indicate the same arrangement of floor, as well as the attic story of a house. The windows of the entresol, or mezzaninro, are usually, from the lowness of the floor, either square, or a little more or less than a square. ENTRY, from the French entrée, and Latin introre, to enter, in law, is a taking possession by the legal owner of lands and tenements when another person is wrongfully in possession of them. At the common law this might be effected by force; but as it was the cause of great abuses, forcible entries were made punishable by sine and imprisonment by two statutes of Richard II., enlarged by a statute of 8 Henry VI. c. 9. (See 1 Ad. and E. 627, and 3 Ad. and E. 817.) A party availing himself of this summary process against an aggressor must enter upon some part of the property claimed, and the safer course is formally to declare that thereby he takes possession of the whole. The entry must be repeated in each county in which the lands lie. This remedy, however, can only be adopted in certain cases, namely, where the original entry of the holder of the land was by unlawful means. In other cases, where the original entry is lawful, and possession held by an apparent right, the owner of the estate must proceed by an action, as an apparent right cannot be legally overthrown by the mere act of a claimant. The Statute of Limitations, 21 James I., c. 16, and the statute 4 and 5 Anne, c. 16, and the more recent enactment 3 and 4 William IV., c. 7, regulate the law on this * and also the periods within which entries may be nna (1e. o Jorcibke, is an entry made with a strong hand, with unusual weapons, an unusual number of servants, or with menace of life; if effected with violence, and the entry only amounts in law to a trespass, it is not within the meaning of the statutes of Richard II. above referred to. The remedy for parties aggrieved, and the mode of obtaining restitution, is either by an action at law, by indictment, or by justices of the peace upon the view. If'made by more than three persons, they may be proceeded against as in a case of a riot. (Bacon's Abridgment ; Burn's Justice.) Entry, writ of, was another method of gaining possession of disputed property by trying the title of the occupant. The earliest mention of this writ occurs in the third year of the reign of Edward III. This writ was directed to the sheriff, requiring him to command the tenant that he render to the demandant the premises in question which he claims to be his right and inheritance, &c. The tenant thereupon was either compelled to deliver up the possession of the land, or to show cause why he refused to do so. This might be done by justifying his own title or that of others under whom he claimed. The claims of the respective parties were then tried before a jury, and the possession of the land was awarded to him who produced the clearest evidence of his right. There were several writs of entry both at the common law and by statute; but they appear to have long fallen into disuse, and but few instances have occurred in modern times of their being resorted to in practice. The learning respecting them, which is somewhat curious, may be found in Reeve's History of the English Law. Under the provisions of the 3rd and 4th William IV.,

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