| Dr. Leach has given some measurements, &c., of the class of boats known as the Rochester barge, the cabins of which are usually very clean; still the above table clearly shows how extremely deficient these vessels are in cubic space, air, and light. Summary.-What is required, then, is firstly systematic inspection of every vessel, whether an ocean-going vessel, an emigrant ship, a coaster, or even a canal-boat, by competent medical inspectors, whose duty would be to see that all legislative enactments relative to the health, comfort, safety, or convenience of the crew were carried out. It is obviously absurd to enact laws, and provide no adequate machinery for the purpose of seeing that they are carried out. It is true that the medical officer of health is responsible for the port to which he is appointed (see SANITARY AUTHORITIES, PORT), but in large ports there ought to be a systematic ship survey. The duty of such inspectors would be to see that a sufficient, and sufficiently varied, supply of food was provided; that the passengers or sailors were in good health; that, in the case of ocean-going vessels, there was a supply of lime juice or vegetables on board; that there was ample provision for water-supply; that emigrants, passengers, or men had the cubic space as laid down by the Duke of Richmond's Act; and special attention should be directed to the forecastle in ships where there is no deckhouse, and to the arrangements for cooking and ventilation. Under manning or overcrowding could, under such a system, hardly fail to be observed and prevented. All vessels carrying passengers, and of any size, should carry a surgeon, whilst the drugs supplied to ships should be examined by the analyst under the Adulteration Act previous to final shipment. If measures such as these were carefully carried out, there is great reason to hope that much preventable waste of life would be decreased; but at the same time it must be confessed that many of the lower class of sailors are addicted to filthy habits, and require sanitation in their own persons as much as the vessels themselves. See HOSPITAL SHIPS; VENTILATION; SHIPS; SANITARY AUTHORITIES, PORT; SCURVY, &c. bulb at each extremity. The one bulb is halffilled with ether, in which the bulb of a delicate thermometer is immersed; the other is covered with muslin. An observation is taken as follows: The muslin is wetted with ether, the evaporation of which quickly cools the bulb and condenses the vapour of ether with which it is filled. As a consequence, evaporation goes on rapidly from the liquid ether in the other bulb, and its temperature falls. The outside of the bulb is narrowly watched, and directly a ring of dew is deposited, at that instant the thermometer is read. The great objection to this hygrometer is that every observation entails a trifling expense. It has generally given place to The Dry and Wet Bulb Thermometers.Now this is simply a special arrangement of two ordinary thermometers, and any two will do, providing they are both constructed of exactly similar materials, and, as a matter of convenience, are adjusted to the same scale. The one thermometer is simply hung on a board near the other, whilst the second has its bulb covered with thin muslin (which must be clean and free from starch). A few threads of the muslin are led into a vessel containing distilled water. The bulbs of both thermometers project below the scales. The necessary precautions in the use of these thermometers are, to see that the muslin is wet the muslin must be either wet, or, in case of temperatures below freezing-point, frozen-and if the temperature should rise above freezingpoint, the muslin still remaining frozen, it must be thawed before an observation is taken. The extreme importance of observations of the difference of temperature between the two thermometers may be gathered from the fact that by their aid the following facts can be ascertained: 1. The dew-point. 2. The elastic force of vapour, or the amount of barometric pressure due to the vapour present in the atmosphere. 3. The quantity of vapour in a cubic foot of air. 4. The additional vapour required to saturate a cubic foot of air. 5. The relative humidity. 6. The weight of a cubic foot of air at the time of the observation. The dew-point and elastic force of vapour are both determined by Dr. Apjohn's formula, and by the aid of Table I. Let F be the elastic force of saturated vapour at the dew-point, f the temperature of the wet bulb-in other words, the elastic force at the temperature of evaporation-d the difference between the dry and wet bulbs, TABLE I.-Showing the ELASTIC FORCE of AQUEOUS VAPOUR in Inches of Mercury from 0° to 80°, calculated from the Experiments of REGNAULT. From Mr. GLAISHER'S Hygrometric Tables. The intermediate Tenths of Degrees may be easily interpolated. ence of temperature of the two bulbs, thus: 2:06 x 5 10:3 = The use of Table II. is to obviate the foregoing calculations. In order to determine the dew-point of the foregoing example by Table II., it is merely necessary to take the factor Now subtract this from the dry-bulb temopposite the temperature of the dry bulb-perature and the product is the dew-part viz., 206-and multiply it by the differ- 50-10·3 = 39.7, as before. TABLE II.-FACTORS for Multiplying the Excess of the Dry-Bulb Thermometer over that of the Wet Bulb, to find the Excess of the Temperature of the Air above that of the Dew-Point. From Mr. GLAISHER'S Hygrometric Tables. The relative humidity, &c., are best determined by the aid of Mr. Glaisher's tables, which every practical meteorologist should possess. The determination of the dew-point is, however, of the most importance-one of its most evident applications being the prediction of frost. If the dew-point in the evening be well above freezing-point, no matter how clear and frosty-looking the sky may look, the absence of frost may be with some conndence predicted; if, on the other hand, the dew-point be 29-4°—that is, below freezingpoint-there will certainly be frost. See AIR, BAROMETER, WIND, &c. Hyoscyamia--The active principle of the Hyoscyamus niger, also found in the thornapple, Datura Stramonium. It may be obtained in silky crystals; very soluble in alcohol and ether. It is difficult to recognise by chemical tests. Sulphuric acid turns it brown. See DATURIA, &c. I. Ice-Water at a temperature below 32° F. (0 C.) freezes and becomes ice. At the moment of congelation it increases in bulk about one-twelfth, and expands so forcibly as to burst the vessel in which it is contained. The most compact ice has a specific gravity of 923. 1000 parts of water at 0° C. become dilated on freezing to about 1083. Water in freezing becomes much purer, losing a large portion, sometimes the whole, of its saline contents, and the air is expelled; hence ice-water may be considered tolerably pure. The ice from a good fresh-water spring is perhaps the purest water in nature. Ice is used in medicine for the purpose of allaying sickness, inflammation, hæmorrhage, and lately it has been recommended as a remedy in the treatment of diphtheria. It is also used in hot weather for the preservation of fish, game, meat, butter, &c. Most large establishments are now furnished with an ice room or chamber, and ocean-going steamers also contain this necessary appliance. Ice is preserved during the summer months by confectioners, &c., in a drained well or excavation, somewhat of the form of an inverted sugar-loaf, contained in a small shed or building called an icehouse. This building should always be situated on a dry sandy soil, and if possible on an eminence, with the door on the north side, and the roof conical and thickly thatched with straw. There are now many machines for the manufacture of ice, and the cost of making it ranges from 2s. 6d. to 10s. per ton. Sufficient cold is obtained in some of the machines by the quick evaporation of liquid ammonia from compressed ammoniacal gas, and in others it is produced by the expansion of compressed air. The custom of eating ices after a hearty and varied meal cannot be too strongly condemned, since the sudden cold stops the flow of gastric juice. Thus digestion is interfered with, and if the practice is persisted in, dyspepsia is inevitable. See FREEZING MIXTURES, &c. Iceland Moss-See LICHEN. Improvement Act, Improvement Act Districts-An "Improvement Act" means an Act for regulating and managing the police of, and for draining, cleansing, paving, lighting, watching, and improving, a place; or it may be an Act for any one of those purposes. 'Improvement Act District" means any area for the time being subject to the jurisdiction of any commissioners, trustees, or other persons invested by any local Act with powers of town government and rating, and empowered under the Local Government Acts to adopt those Acts, or any parts thereof. Every Improvement Act district is now an urban sanitary authority. Provision is made by P. H., s. 310, in case of an Improvement Act district or local government district becoming a borough, that all rights, duties. liabilities, &c., of the Improvement Act district, or local board, as the case may be, shall pass to, and be vested in, the council of the borough. See SANITARY DISTRICTS. Indian-Corn-Common maize or Indiancorn (Zea Mays) is a native of tropical America, and is now extensively cultivated in the United States, Africa, Southern Europe, Germany, and Ireland. The grains usually met with are of a yellow colour. Letheby gives the following, as showing the composition of Indian-corn meal :— By the aid of the microscope it may be seen that the testa of Indian-corn is composed of two membranes, the outer of which is made up of several layers of oblong cells, the inner of only a single layer of cells. The cells of the cellulose make up the remainder of the seed. They form a cellulated network, each space holding a starch corpuscle. The starch corpuscles show under the polariscope a black cross. They are disc-shaped, with a central concavity, and generally show a divided and radiate hilum (see fig. 51). Indian-corn is largely eaten all over the world, but more especially in tropical countries. The ration for a Kafir servant is 3 pints of Indian-corn meal per day, and on this scanty allowance-for he gets little else-be manages to keep in good health. Indian-corn has since 1846-the potato-famine year-been largely used in Ireland. It is stirred into boiling water or boiling milk, and formed into a sort of hasty-pudding, or thick porridge, no exhilaration, and rather absence of thought, Indian-corn, being deficient in gluten, does not make good bread. Its flavour is harsh and peculiar. A weak solution of caustic potash removes this unpleasantness; but it also deprives it of much of its nitrogenous matter, and so renders it less nutritious than before. This is the foundation of the process for preparing the articles extensively sold under the names of Oswego, Maizena, and Corn-flour. As a mere adjuvant, or auxiliary, prepared Indian-corn may be of value, but mothers and nurses should be earnestly cautioned against injudiciously giving it to infants. See INFANTS, DIET OF. Indian Hemp-The dried flowering tops of the female plants of Cannabis sativa, Linn. (natural order Urticaceae.) For medicinal use that which is grown in India, and from which the resin has not been removed, is alone to be employed. The parts employed in Asia for the purposes of intoxication are the herb or leaves, and the resin. Indian hemp contains a resin (cannabine) soluble in alcohol and ether, but precipitated by water; to this resin the plant owes its active properties. The other principles which have been separated are gum, extractive, and an ethereal oil. Indian hemp produces a peculiar kind of intoxication, with hallucinations of a pleasing kind. It is said to act as an aphrodisiac, and to augment the appetite for food. It is much used in the East, and preparations of it are sold under the name of "Hashish Bhang," "Gunjab," &c. "Gunjab-smoking," says Dr. Chevers, "is ascertained to be the cause of a very large proportion of the cases of acute mania admitted to the native lunatic asylum of Bengal." 46 Dr. As an intoxicant it is certainly not used to any extent in England, and as a medicine it has much disappointed practitioners. Froumuller suggests that the drug contains some ethereal ingredient which is dissipated in the voyage from India; for he has seen in that country marked effects from half a grain of the extract or even less, so that he had been accustomed to consider a grain and a half a large dose; while in England he had found it necessary to give ten, twelve, or more grains to produce the desired effect. The present writer has seen it produce in England, when taken in large doses for the purpose of experiment, a sleepy, stupid state of drunkenness. There was certainly little or Infants, Diet of - Carefully - collected statistics, allied to general observation and particular experiments, have conclusively proved that, as a food for young infants, nothing has yet been found which can take the place of milk. Dr. West, in his valuable "Lectures on the Diseases of Infancy and Childhood," says: "The infant whose mother refuses to perform towards it a mother's part, or who by accident, disease, or death is deprived of the food that nature destined for it, too often languishes and dies. Such children you may see with no fat to give plumpness to their limbs, no red particles in their blood to impart a healthy hue to their skin, their face wearing in infancy the lineaments of age, their voice a constant wail, their whole aspect an embodiment of woe. But give to such children the food that nature destined for them, and if the remedy do not come too late to save them, the mournful cry will cease, the face will assume a look of content, by degrees the features of infancy will disclose themselves, the limbs will grow round, the skin pure red and white, and when at length we hear the merry laugh of babyhood, it seems almost as if the little sufferer of some weeks before must have been a changeling, and this the real child brought back from fairyland." Those who have visited the wretched homes of women employed at factories, or of the pernicious baby-farmers, will be able to endorse fully Dr. West's words. Milk- and it is the mother's milk to which we now particularly refer contains the principles required for the growth and nourishment of the child, and contains them in such a form as to be easily assimilated. For the first few months but little saliva is secreted; the teeth do not appear for some time; and the digestive organs of the child are so extremely susceptible of derangement that it is necessary even for the mother to exercise the greatest caution over what she herself eats. All this tends to show that the digestive capacity is extremely feeble-nay, often, until after the eighth month, absolutely incapable of assimilating anything but milk. When from an unnatural objection on the part of the mother, from disease, from death, or any other cause, the child does not receive the aliment prepared and elaborated by nature for its sustenance, then, undoubtedly, the nearest approach to the actual food given in the milk of the parent is the milk furnished by another woman. |