The milk of the goat is very white, sweetish, and of an unctuous taste. Its specific gravity is 1036. It is affected by re-agents nearly as asses' milk. The cream is very thick, of a mild agreeable taste, and slowly proceeds to acidity. It easily forms butter, which is white, firm, and consistent; and, from its thickness, is easily converted into a very rich cheese, which is not soon injured by keeping. The butter milk abounds with cheesy matter, which may be separated by acids. The quantity of cheese which this milk affords is its chief characteristic. The curd is so copious that the whey separates with difficulty. The curd is also gelatinous and consistent, while in female or asses' milk it is in

5 Q 2 divided particles. The cheese is peculiarly rich and agreeable The butter is white and rich, but not as from asses' milk in consequence of a mixture of the curd, for none is deposited on melting. On this account it keeps long without spoiling. Sixteen hundred parts of this milk contain 127 of cream; 72 of butter; 146 of cheese; 70 of sugar of milk, of which one fourth is lactic acid. The saccharine matter appears to be less than in female or asses' milk. Its sugar white when the serum spontaneously evaporates. When artificial heat is used it becomes a jelly, and the crystals are coloured. The serum contains a very small proportion of common salt.

The milk of the sheep greatly resembles that of the cow. Its specific gravity is 1035, and it readily runs into the acetous fermentation in summer. When at rest, a thick, rich, sweet, yellowish cream rises in considerable quantities, which affords much butter; but it is oily to the taste, and its consistence is not considerable. It easily becomes rancid if not well washed. Its cheese is rich and viscous, but mild and agreeable. The serum affords a very white sugar. Sixteen hundred parts afford 185 of cream; ninety-three of butter; 246 of cheese; and sixty-seven of sugar, of which one fourth was lactic acid, and as much was obtained from the remaining fluid. All the acids (except the carbonic acid gas), alum, and liver of sulphur, coagulate it. Kali and soda render its colour dark; if caustic, red; ammonia, which also attenuates it, yellow. The neutral salts have no effect on it. The characteristics of this milk are the quantity of cream it furnishes, the quantity and richness of its cheese. The famous Roquefort cheese owes its excellence to the mixture of sheep's curd. Annales de Chimie, iv. 31.

The milk of the mare retains the smell of the animal, and it tastes as if water was mixed with it, though its specific gravity is 1045. The mineral acids coagulate it; the phosphoric deprives it of its colour and opacity; the fluor and saccharine acids slightly coagulate it when warm. Lime water precipitates a caseous matter when warm; alcohol renders it slightly curdy; rennet has no effect on it. Mare's milk is remarkable for its fluidity, but it is less so than female's or asses ' milk, and more tasteless than either. Parmentier informs us that it easily boils, and is not difficult to coagulate. Its distilled water is nearly inodorous, and its franchipan less copious and unctuous than that of the cow. On a alight heat this milk is covered with pellicles, and the first are the most unctuous. The cream rises soon, is yellowish and clear, but produces no butter. The skimmed milk resembles that of the cow, but the vegetable acids separate slowly the cheese, and in a form resembling that from human milk. The serum afforded a vitriolated lime in needle like crystals, and sugar of milk in the form of a saline concretion. The mother water was found to contain muriat of lime. Sixteen hundred parts afforded only thirteen of cream; twenty-six of cheese; 140 of sugar of milk, of which about forty were lactic acid. From mare's milk the ardent spirit is chiefly procured. The art of making it is of great antiquity, and consists in not permitting the separation of the component parts of the milk, or again uniting them, if separated, till an acidity is observed. The spirit is apparently developed at the same time with the acid.

It is remarked by Parmentier, that when cows are diseased, the albuminous curd is the only part changed The corresponding part of other animal fluids seems. alone, to suffer from a morbid state of the body.

Stipriaan gives a short comparison of different milks, which we shall subjoin. The most aqueous, he observes, is the milk of the ass. Then follows that of the mare, the human female, the cow, the goat, and the sheep. Cream was most abundant in sheep's milk; next in the human, the goat's, cow's, ass's, and mare's milk. Butter was in the largest proportion in sheep's milk, next the goat's, cow's, and human milk. Cheese abounded most in sheep's, then successively in goat's, cow's, ass's, human, and mare's milk. Most sugar was afforded by mare's milk, followed by the human, the ass's, the goat's, the sheep's, and the cow's milk. Parmentier divides milks into two classes, the serous and the caseous, or butyraceous. The first contains asses, mares, and human; the second, the cow's, the goat's, and the sheep's milks.

These facts, which have not been hitherto collected in any medical work, point out the absurdity of numerous directions, which fill the volumes of dietetic writers, and those authors who have written on the diseases of children. Women's milk, as we have said, is so various, that general rules can scarcely be drawn; but if any fact respecting it is better established than another, it is, that acids will not coagulate it. We have already observed, that milk must be coagulated before it can become subject to the digestive powers, and this is consonant to another fact, noticed in the article Digestion, q. v. that, unless the food or drink is delayed in the stomach, though absorbed, it is soon again carried to the excretory organs, as a substance foreign from the habit. This is even the case with water. That milk must be coagulated in the stomach is proved, not only by these circumstances, but by infants vomiting milk as it is taken in, when any disease occurs in the stomach, and their occasionally vomiting it in a coagulated state, when the discharge has been accidental, or from fulness. We recollect some experiments made, many years since, by Mr. Wilson, though we believe not published, in which, after the most attentive examination, no acid could be detected in the stomach of infants. We now see, that if it had been there it would not have produced coagulation. Acid, we know, does occasionally abound in the stomachs of infants, because we find it changing the colour of the bile; but it is not constantly present, and still less is it necessary to assist the digestive process. To assist in this enquiry, we mentioned the effect of rennet, (the stomach of the calf,) though carefully washed and dried, in coagulating cow's milk, and added a fact from Spallanzani, that the liver of the turkey would produce a similar change. Why may not the stomach of a child, and, in a less degree, that of an adult, occasion the coagulation? But, though this be not granted, we have seen that, when human milk has been once coagulated, the former coagulum is sufficient to produce this change in fresh milk; and this is certainly the most common cause. From these observations, we may, at least, draw one inference, that absorbents are too commonly given to children. Acid in the stomach seldom produces any bad effect. It is carried off like any foreign body, and soon neutralized by the bile. Our predecessors, in practice, used them freely; but by employing the animal earths, they fortunately did not always exhibit an absoibent, and only threw into the stomach a small quantity of an indigestible powder, which was soon again discharged. Such was the Gas-coyne's powder, the pearls, and a great variety of costly and fashionable medicines.