envelope, and then evaporating on the object glass of a microscope. Crystals were subsequently obtained, in the same way, from the blood of a great variety of fishes, of dogs, rats, mice, and squirrels. M. Lehman has obtained crystals on a larger scale (having in the case of the guinea pig a diameter of three-fourth line) in the following way: Blood is mixed with water, alcohol, or ether; or which is best, ether and water, and introduced into a cylindrical vessel closed at one end with pigs bladder permeable to water, and at the other by coutchouc permeable to ether and alcohol; as this last passes off by endosmosis the blood becomes turbid; the instrument is then left to itself at a temperature from 55° to 68°F. As the liquids evaporate the crystals form; they are purified by washing and lixiviation with water in which they dissolve with difficulty. To free them entirely from the envelope they must be dissolved in water at from 104° to 122°F., and the liquid filtered. They crystalize with difficulty from the solution.— His analysis has led M. Lehman to think that they are formed by the combination of an albuminoid substance with mineral matter. They contain much water of crystalization, and are efflorescent. Their solution coagulates at from 143° to 157° F.; it is not precipitated by acetic acid, but is by the mineral acids, alcohol, and in general by those re-agents which precipitate albumen.

N. Y. Edit. Lond. Lancet for 1852, Vol. 2, page 309. V. Magendie analyzing the blood drawn on the 6th, 8th, 15th, and 17th days from a glandered mare, deprived of all solid food and allowed but a limited quantity of water, and which died on the 24th day, found the solid constituents to be increased at each bleeding. It appeared probable that the albumen and fibrine, although as well as the globules increased in quantity, had been altered in quality; for two days before death the blood did not coagulate, and after death was found to be acid. The change appears to have been the effect of abstinence, inasmuch as in a similar experiment upon a healthy dog, analogous results were obtained.

London Lancet, Vol. 2, page 309.

VI. M. M. Becquerel and Rodier inform us that in most prolonged chronic diseases, especially in organic diseases of the heart, Bright's disease, chlorosis, paludal cachexia, hemorrhages, cancerous diathesis and the last periods of tubercalosis, also in cases of insufficient nourishment or air, and of continued humidity or want of light, the red particles are diminished in quantity. This diminution is shown especially by discoloration of the skin, dyspnoea, palpitation, systolic murmur at the base of the heart, and arterial and venous murmurs.

In the last stages of heart disease, great symptomatic anæmia, cancerous diathesis, and insufficient nourishment, the albumen is diminished. This diminution produces dropsy, and is the cause of most essential dropsies.

In chlorosis, the fibrine may be unchanged or augmented. In acute scurvy the blood may be unchanged, or there may be an increase of fibrint. In Bright's disease, the fibrine is not changed in the acute stage, and may be unchanged or diminished in the chronic. In chronic scurvy or the scorbutic condition symptomatic of some chronic diseases, especially of the heart, the fibrine is diminished. This diminution is shown by cutaneous and mucous hemorrhages.

In general, when the other constituents of the blood are diminished the water is augmented. In anæmia, symptomatic of great hemorrhages, excessive catamenia or bad food, the fibrine is unchanged, the albumen unchanged, or slightly diminished, the red particles and specific gravity are dimished and the water increased.

FAT.

London Lancet Vol. 2, page 308. B. S. Schultze mentions as the probable sources of fat, 1st, fat previously existing in the food; 2d, non-nitrogenous, nonfatty food; 3d, nitrogenous food; and 4th, the other tissues of the body. Of the first three, which alone are physiological, the first must be unquestioned; the production of butyric acid from sugar and the formation by the bee of wax, (which is analogous to fat,) from honey, are mentioned as proofs of its production from the second source. The claim of the third class of snbstances to be considered a source of fat, rest upon certain experiments which he does not consider conclusive. He however supposes that in disease, but not in a state of health, albuminous, and other food containing nitrogen, can be changed to fat.

Respiration and cutaneous transpiration greatly influence the deposition of fat, it being inversely as their activity. The fat taken in with the food serves principally to support respiration. The influence of the kidneys, though it appears that they may sometimes separate fat, is far less than that of the lungs and skin. The liver also appears to seperate fat from the system, that substance having been found in the bile and fæces, and impairment of the functions of the liver sometimes tending to promote the deposition of fat. Schmidt and others supposed that the chyle never contained more than a normal quantity of fat. Schultze however thinks that the

quantity will vary with the nature of the food, and its excess may lead to disease.

He controverts the opinion of Reinhart, that granular cells are the result of retrogade metamorphosis.

MILK.

Chemist N. S., Vol. 4, page 273. M. M. Vernois and Alfred Becquerel, have analyzed human milk under a variety of circumstances. They find normal milk to be composed of water, 889.08 parts; sugar, 43.64; caseum and extractive matters, 39.34; butter, 26.66; and salt, 1.38 and its density to be 1032.67.

Except in extreme cases the age of the nurse does not appear to modify the density; the milk of a woman aged from 15 to 20 contained somewhat more solid matter than that of of one from 35 to 40. The milk of primiparous nurses approaches more nearly the mean than that of multiparous. In the collostral state the butter is considerably augmented. Advanced gestation increases the quantity of solid constituents. Menstruation diminishes the water and sugar, it augments the weight of the solid parts, especially of the caseum. Sparing diet increases too much the water. In feeble constitutions the milk is nearly normal; in the robust the solid parts are diminished.

In acute diseases the respiratory elements are diminished and the nutritive increased; in the chronic the reverse change occurs. In both there is a loss of water and density. The constitution of milk in acute and chronic disease is exhibited in the following table:

In cases of pulmonary tubercles without diarrhoea, or emaciation, few changes are perceptible; if however these symptons be present, the weight of solid matter is greatly reduced, the loss being exclusively butter. In syphilis the butter is dimished and the salts and density greatly increased.

The proximate principles of the milk appear to be entirely independent one of another; each being in its developement modified by peculiar influences.

URINE.

N. Y. Edition London Lancet, Vol. 1, page 455. I. Dr. Martin Barry, has reported Liebig's method of determining the quantity of urea in urine, substituting graduated measures for weights. His test is pernitrate of mercury. It is necessary to obviate the influence of two substances always present in the secretion, phosphoric acid, which would give a precipitate with the test, and chlorine, which would form bichloride of mercury and thus prevent the precipitation of the urea. The acid is removed by baryta, and the action of the chlorine is compensated for by an equivalent of pernitrate of mercury, it being cautiously added until a precipitate begins to appear. A solution of the test, of known strength, is then added, from a graduated measure, just as long as precipitation occurs. Simple inspection of the measure shows how much of the test has been used, and from it the quantity of urea is easily calculated.

Chem. Gaz. Vol. 10, page 345.

II. Dr. W. Marcet, has discovered a method of isolating the urea of urine, and has been able by this process to obtain that principle in much larger quantities than usual.

He evaporates the fluid to dryness, dries the residue over sulphuric acid, and then subjects it to the action of boiling alcohol, adding this in small quantities and decanting each time before adding a fresh portion. By repeating this till the alcohol comes off colorless, he separates all the urea. He now

pours a little sulphuric ether down the side of the vessel containing the solution, so as to avoid mixing the liquids. Immediately upon the ether reaching the alcoholic solution of urea a cloud is formed. He continues the addition until the precipitation ceases. In a few hours the precipitate disappears, and the sides and bottom of the vessel is found lined with beautiful crystals of urea. It is purified from a little adhering chloride of sodium by crystalization from water. He is led to conclude that the urea exists almost entirely uncombined in the urine; and he has discovered in that secretion two new substances with acid reaction.

The etherial solution, after the deposition of the urea, is decanted, neutralized with baryta water, to prevent decomposition of the acids, and concentrated on a sand bath, the alcohol and ether having disappeared, the baryta salt is decomposed by sulphuric acid, the mixture is shaken with common

alcohol and filtered. The filtrate is an alcoholic solution of urea and the new substances with a very acid reaction. It is washed with water and either, and on standing gradually seperates into two layers; the upper is a rose colored ethereal solution of the acids; and the lower consists of water,alcohol, sulphuric acid and urea. The ethereal acid solution is, washed repeatedly with dilute alcohol and then with water decanting after each washing. It is then exposed at common temperatures to the air; at the end of 24 hours there are found numerous small colorless crystals on a watery liquid, and an intensely rose colored resinous acid substance on the sides of the vessel.

These crystals strongly resemble hippuric acid, but when fused they diffuse an odour very different from that of hippuric acid, and without taking fire they become charred and finally disappear. This acid appears to be in union with some base in the urine, or, if free, to be decomposed by the heat necessary for concentration, as it cannot be obtained without the use of baryta and sulphuric acid.

The rose colored substance has a stronger acid reaction than the crystals. It is insoluble in water, but soluble in hot ether or hot alcohol. Heated on platinum, it diffuses an odour of burnt oil becomes charred and totally disappears. After 4 or 5 days it deposits crystals quite different from the other acid. It can be separated without the aid of sulphuric acid, and therefore appears to exist in a free state in the secretion.

Neither of these acids contain the least trace of sulphuric acid.

N. Y. Edit. Lond Lancet, Vol. 2, page 197. III. Dr. Arthur Hassel has published some interesting remarks on the chemistry and pathology of urine. He rejects the opinion of Dumas, that the conversion of urea into carbonate ammonia, is owing to the mucus acting as a ferment. He thinks the cause of this change is now better understood

The conversion of urea into carbonate of ammonia is promoted by the presence of alkalies and retarded by acids.Urine, when voided, may be alkaline, neutral or acid. Urine that is alkaline when discharged may be so from fixed or volatile alkali, or both; and this may proceed from fixed alkali, or alkaline blood reacting upon the urea, while in the circulatory system. Out of the body this condition will greatly expedite the change of the urea; but a much more frequent cause is the presence of carbonate of ammonia, resulting from the decomposition of the mucus, which is in general the first change towards an alkaline condition in neutral urine.Ascidity and absence of heat retard the change; it also pro