minister and interpreter of the thoughts, feelings, and emotions of the mind, the author maintained that, in all cases of loss of speech which are of cerebral origin, there is involved either structural change or functional derangement in the nervous apparatus of the intellectual consciousness. The author briefly narrated two illustrative cases out of a number which had come under his observation, one of structural change, and the other of functional derangement, both of striking significance. But the point which he wished especially to impress upon every physiological psychologist was this, viz. that the power of giving utterance to our thoughts and ideas in appropriate language depends upon the due relation being maintained in its integrity between the centres of intellectual action and the encephalic motor centres through which the volitional power is exercised in articulate speech-in other words, between the cerebral hemispheres and the corpora striata. For thoughts and ideas might be moulded for expression in the seat of intellectual action, but the agency of the will or volitional power to give them utterance requires the integrity of the motor centres, through which the volitional impulses operate on speech. The author said a special cerebral organ had been assigned to the faculty of speech, and that the illustrious Gall was the first to locate it in the anterior lobes of the brain. Since his time the subject had undergone much discussion in France, and conflicting evidence had been adduced. He adverted to the hypothesis of Dr. Dax, that the left hemisphere of the brain was its exclusive seat, but to which he could not subscribe. The brain is a double organ; the functions of both hemispheres are identical, in harmonious accordance with the doubleness of the organs of sense, as double inlets to knowledge. Professor Broca, who claimed the honour of being the first to discover that the third convolution was the seat of the faculty of articulate speech, was constrained to admit that the function was not exclusively exercised on the left side of the brain, although disease there, with hemiplegia of the right side, was almost universally characterized by aphasia, The author, in proof that the right hemisphere exercised the same function in regard to articulate speech as the left, adduced a case in which there was extensive disease in the left hemisphere, on the very site of Broca's organ, and yet during life the faculty of speech was not impaired.

On the Homologies and Notation of the Teeth of Mammalia.
By W. H. FLOWER, F.R.S., F.L.S.

After some introductory observations, the author stated that the subject which he proposed to bring before the Meeting was an endeavour to ascertain how much of the generally adopted system of classification and notation of the teeth of the Mammalia-a system mainly owing to the researches of Professor Owen, whose labours in this department of anatomy no follower in the same field could fail to recognize gratefully-stands the test of renewed investigations, how much seems doubtful and requires further examination before it can be received into the common stock of scientific knowledge, and how much (if any) is at actual variance with well-ascertained facts.

One of the most important of the generalizations alluded to is the division of the class Mammalia, in regard to the times of formation and the succession of their teeth into two groups-the Monophyodonts, or those that generate a single set of teeth, and the Diphyodonts, or those that generate two sets of teeth. The Monophyodonts include the orders Monotremata, Edentata, and Cetacea; all the rest of the class being Diphyodonts. The teeth of the former group are more simple and uniform in character, not distinctly divisible into sets to which the terms incisor, canine, premolar, and molar have been applied, and follow no known numerical law. The group is, in fact, equivalent to that to which the term Homodont has been applied by some authors. On the other hand, in the mammalian orders with two sets of teeth, these organs are said to acquire fixed individual characters, to receive special denominations, and can be determined from species to species, the animals so characterized being Heterodonts.

The author then showed that among the homodonts, the nine-banded Armadillo was certainly a diphyodont, having two complete sets of teeth, and among the heterodonts, many were partially, and probably some completely, monophyodont.

Moreover that almost every intermediate condition between complete diphyodont and simple monophyodont dentition existed, citing especially the Sirenia, Elephants, Rodents, and Marsupials. He then, by the aid of diagrams, showed particularly two modes of transition between monophyodont and diphyodont dentition—one in which the number of teeth changed was reduced to a single one on each side of each jaw, as in Marsupials, and the other in which the first set of teeth, retaining their full number, were reduced to mere functionless rudiments, and even disappearing before birth, as in the case of the seals, especially the great Elephant seal. These observations showed that the terms "monophyodont" and "diphyodont," though useful additions to our language, as means of indicating briefly certain physiological conditions, have not, as applied to the mammalian class, precisely the same significance that their author originally attributed to them.

The classification and special homologies of the teeth of the heterodont mammals was next discussed. Certain generalizations as to the prevailing number of each kind of teeth in different groups of animals were sustained, but deviations were shown from some of the rules laid down, such as that when the premolars fall short of the typical number, the absent ones are from the fore part of the series. The general inference was, that, although in the main the system of notation of the mammalian teeth, proposed by Professor Owen, was a great advance upon any one previously advocated, we must hesitate before adopting it as final and complete in all its details, and need not relax in our endeavour to discover some more certain methods of determination.

On the Anatomy of the Carinaria Mediterranea. By ROBERT GARNER, F.L.S.

In this paper the author gave the anatomy of a male and female specimen, without any reference to the descriptions of previous observers, as Delle Chiaje, Verany, and others. The cylindrical form of the animal, finned tail, curiously modified molluscan foot, and the viscera excluded, as it were, by hernia, from the body, and covered by the delicate shell, are tolerably well known. The envelope or tegument, though tuberculated or spiny, as well as covered with small and larger granulated opacities, and mottled with brown, is so diaphanous that the stomach and first part of the intestine can be seen through it. A second inner coat is composed of a beautiful network of muscular fibres, but the tail has fascicles only from this coat. The foot or abdominal fin, carried, however, upwards as the animal swims, is neatly reticulate and tinged with rose-colour, and has a little suctorial disk on its posterior edge. The sea-water is admitted into the body of the animal by a pore behind this fin. The animal has a retractile trunk, and tentacles with well-developed eyes. Within the muscular sac, besides the stomach and first part of the intestine, is little else but the buccal apparatus, two salivary glands opening near the commencement of the gullet, the brain and pedal ganglion, and aorta. The ribbon of lingual teeth is pretty simple-a tricuspate broad tooth in the centre, a large hook on each side laterally, and between the two another piece with a long and short point. These teeth dissolve in boiling nitric acid, and consequently are not siliceous. The buccal box itself is ample, with six or seven pairs of extraneous muscles, besides powerful intrinsic ones attached to its cartilaginous basis. The stomach, which immediately succeeds, contained remains of Pteropoda (small conical Cleodora), of small Cephalopoda, and portions of the lingual ribbons of its own species; also beautiful discous and other Diatoms. The bulk of the viscera are covered by the shell, which also has attached to it the muscles, with much the same disposition as is seen in a Patella. The intestine entering this nucleus makes many convolutions at the front of the shell, and then opens on the right side under the margin of the shell and mantle. The brain is supra-oesophageal, and is seen to consist of three amalgamated pairs of ganglia. Of course it gives nerves to the eyes and feelers close at hand, the former having large lenses covered by the transparent skin; also to the mouth, and is connected with two little ganglia situated on the buccal box. Four nerves go backwards from the lateral and posterior parts of the brain, two forming a lobed ganglion near the abdominal fin, supplying it and the tail, and two rising towards the viscera, forming a ganglion at the root of the branchiæ. There are also two nervous enlargements near the pylorus, and auditory sacs on the pedal ganglion.

The branchiæ, about twelve-divided, lie across the fore part of the mouth of the shell, attached on the left side, where are the heart and branchial veins; on the right is the branchial artery, receiving a large branch from the renal organ situated above. Higher still in the shell is the liver with its bile-ducts, and above the liver, in the recess of the shell, the testis in the male and the ovary in the female. The duct from each goes downwards; in the male it opens into a sinus of the integument of the right side, where is also seen, at its termination, a little twisted exsertile body, but which sinus does not exist in the female, the opening being higher, close to the vent, where it is also joined by niditamentary organs; one elongated, the other oval, both laminated within, and the latter dark purple without; in microscopic structure these seemed to be composed of small globular bodies. The testis contained globules, probably endosmosed spermatozoa; the ovary, evident_ova. The female specimen was a good deal the larger, and the tail more obtuse than in the male.

On the Albuminoid Substances of the Blood-corpuscles.
By Professor HEYNSIUS.

On the Nomenclature of Mammalian Teeth and the Teeth of the Mole.
By E. R. LANKESTER and H. N. MOSELY.

The authors pointed out the arbitrary and misleading nature of the division of teeth into incisors, canines, premolars, and molars, since to these terms might fairly be added sectorial, bicuspid, tricuspid, laniary; secondly, they show that maxillary and premaxillary are the only divisions admitting of homological identification, the maxillary teeth being further divided into an anterior and posterior series in most diphyodonts, by means of the fourth so-called premolar. They pointed out that there is no homology of upper with lower jaw teeth, and that the present rule for their identification is most arbitrary and unscientific. They show that the so-called canine of the mole is a premaxiliary tooth, that animal being thus the only placental mammal with eight premaxillary or incisor teeth. The authors further describe a new tooth in the badger, making its dentition identical with that of the glutton; this tooth belongs to that series of "premolars" which have no milk-predecessors as described by Mr. Flower recently in the dog and pig, and very rapidly drops out of the jaw.

Notes on the Homologies and Comparative Anatomy of the Atlas and Axis. By ALEXANDER MACALISTER, L.R.C.S.I.

It seems to be a principle in morphology that the greater the amount of specialization of function manifested by any organ, the further does the structure so specialized depart from the form of the primordial type to which it belongs. This principle is particularly exemplified in the case of the two upper cervical vertebræ, the atlas, and the axis, as on account of the special varieties of motion of this region it is in some instances difficult to assign to the parts of these bones their exact positions as serial homologues of the processes in other vertebral segments. We owe much of our knowledge of the relations of these bones to Owen, Rathke, Cleland, and Robin; but a few points yet require to be wrought out with regard to them, so as to enable us to understand more clearly the homologies of their several portions. In order to present a more complete series of relationships between these bones and the ordinary cervical vertebræ, the points to be considered are the following:-(1) the nature and homologies of the body, of the axis, and of the odontoid process; (2) the nature of the preodontoid half-arch of the atlas; (3) the serial homologies of the transverse atlantal ligament and of the occipito-axial or check ligament; (4) the third occipital condyle of Meckel and Halbertsma; (5) the articular processes of the atlas and axis; and (6) the transverse processes of the cervical vertebræ in general, and of these two in particular.

These may be briefly summarized thus:

:-

(1) The odontoid process is the body of the atlas; a considerable amount of evidence on this point is contained in the original paper.

(2) The preodontoid half-arch of the atlas is considered by Koster as a hæmal arch, by Owen as a hypapophysis; but in the author's paper reasons are given for considering it as an ossified anterior conjugal ligament, like the middle slip of the stellate thoracic ligament.

(3) The transverse ligament of the check-ligaments are serial with the conjugal ligament of the ribs.

(4) The third occipital condyle is homologous with the central part of the ornithic and reptilian condyle.

And lastly, the articular surfaces of the atlas and occipital bone are structurally double, the anterior part being in series with Luschka's Halswirbel, the posterior part being probably related to the true oblique process.

On the Transmission of Light through Animal Bodies.
By Dr. RICHARDSON, M.A., F.R.S.

The author exhibited a lamp which he had constructed for transmitting light through the structures of the animal body. He believed the first idea that such transmission could be effected was given in Priestley's work on Electricity. That great experimentalist, the Shakspeare of physical science, had observed, on passing a discharge of a Leyden battery through his finger, that the structure seemed to present luminosity, but the operation was extremely painful. The author had repeated this experiment with similar results. Of late years research had been made with the microscope in the transparent web of the foot of the frog; and last year Dr. M'Intosh had shown that young trout could be used experimentally, they being sufficiently transparent for the investigation of the action of various poisonous substances on their internal organs. The suggestion of Dr. M'Intosh had been acted upon by the author, and the motion of the heart and of the respiration had been observed by direct ocular demonstration while those organs were under the influences of various bodies belonging to the ethyl and methyl series. This research had led the author to extend the principle further; and he had now advanced so far that he was enabled to transmit light through various tissues of the bodies of large animals. He had thought it was best to begin by testing each tissue separately; and this investigation had been carried out on nearly all the structures of the body which admit of being individually examined. The structure the most diaphanous was the skin; after that, and singularly enough, bone; then thick membranes; next, thin superficial muscles, lung tissue, fat, and the dense tissues of the liver and the kidney. Various lights had been tried, viz. the electric, the oxyhydrogen, the lime-light, and the magnesium. For all practical purposes, the magnesium light was the best: it was the most convenient to use, and the light had the advantage of penetrating deeply. In the lantern which the author exhibited the light was also unattended with heat at the point of observation, so that the hand could be put in at the brightest illuminating point. The lamp was made by Solomon, of Red Lion Square. The additions consisted in a tubular arrangement and a sliding groove. The structure to be examined was placed in the groove inclosed between two disks of perforated wood, and the object was surveyed from the further end of the tube. In illustration, a thick piece of bone (the flat rib of an ox) was placed in the lantern, and light was distinctly transmitted through it. "It was," said the author, "important to speak with care as to the extent to which this lantern could be used practically." He did not consider it perfect, but thought it promised results of the greatest interest and value. In the first place, it might be used for a variety of physiological purposes. Animals whose tissues were thin, such as fish, could be placed in the lantern, and the condition of their circulation and respiration could be carefully studied under the action of various agents. In the human subject, especially in the young, having fragile tissues, the thinner parts of the body could be distinctly rendered transparent; and in a child the bones, under a somewhat subdued light, could be seen

in the arm and wrist. A fracture in a bone could, in fact, be easily made out, or growth from bone in these parts. In a very thin young subject, the movements and outline of the heart could also be faintly seen in the chest; but the light he had as yet employed had not been sufficiently powerful to render this demonstration all he could desire. It would be possible, lastly, to see through some diseased structure, so as to ascertain whether, within a cavity, there was a fluid or a solid body. The author concluded by stating that his object had been rather to mark the origin of a new and progressive step than to explain a perfect instrument, or record an extended series of successful results.

On Effects of Extreme Cold on Organic Function.
By Dr. RICHARDSON, F.R.S.

In

The author passed in brief review his experiments performed at Dundee in relation to the effects of feezing the centres of the nervous system. He showed that in the lower classes of animals, such as frogs, the nervous centres can be frozen for long periods of time, with recovery after entire unconsciousness and apparent death. The points added on this occasion were in continuation of this line of research. The author first dwelt on the question whether frozen animals (such as frogs) respire during insensibility, and explained that they did not. proof of this he said that animals so treated could be placed without harm in gases which would not support life, such as nitrogen and hydrogen, and could be recovered at the precise moment of solution from the frozen state when respiration was recommencing. He had placed animals in this way in hydrogen, nitrogen, and carbonic acid. In other experiments, when the animal was frozen, it was immersed in ether, and allowed to lie under the fluid until, by the rising of bubbles of air, indications of returning life were gained; then, taken out, the animal would recover. The gradual return of heat was thus a pure restorative, and the facts helped to explain many accounts as to restoration after freezing, which up to this time had been stated as strongly on one side as they were doubted on the other. The second point considered had relation to the effects on the circulation of freezing the brain. The author here showed that in warm-blooded animals the effect of reducing the temperature of the brain was to produce a gradual slowness of the circulation, and, when the freezing was carried to the lower part or base of the brain, to produce the condition of heart and pulse known as intermittency, followed, if the operation were continued, by the entire cessation of the heart's movement. This was a point of great practical moment as indicating the influence of the brain on the heart. Whenever the brain was reduced in physical power, as from intense mental fatigue, or shock, or anxiety, irregular action (intermittency of the heart) was almost the necessary result. Most people were conscious of this, and often thought with great alarm that they were suffering from disease of the heart, when in fact they were merely labouring under temporary exhaustion of the brain. The third point went to show that under the influence of extreme cold on the nervous centres (the brain and spinal cord) the extreme effect of such active poisons as strychnine could for a time be entirely suspended. This raised a hope that in such diseases as tetanus, a new and successful mode of treatment might be gradually evolved. The fourth point had relation to the influence of extreme cold in preventing and even in removing the rigidity of death. Because the body after death cools, the inference had been drawn that the rigidity of death was due to the process of cooling. This was the exact reverse of the fact. The rigidity of death was quickened by heat, and prevented by cold, probably for an illimitable period of time, the cold being sustained. Further, by taking an animal already rigid, freezing it, and thawing, the first rigidity could be removed and the body become flaccid. The last point touched upon related to the effect of freezing and rapidly thawing the skin of certain regions of the body. It was shown that birds treated in this manner presented the extremest irregularity of movement, and other signs of nervous disturbance. Thus by freezing and rapidly thawing the skin on the side of the neck of a pigeon, the bird for a time walked sideways in the opposite direction. The author designated this effect as peripheral nervous shock.