in itself, in no way chemically differs from healthy milk; (4.) that it is only by biological methods of experiment that such diseased milk can be detected. These remarks apply only to the composition of the milk; but if we also regard the quantity secreted, then there is in all cases a remarkable difference, for whenever an animal suffers from a sufficient amount of disease to affect its health materially, the diminution in the total quantity of milk is almost invariable.

I. HUMAN MILK.

§ 154. With regard to the milk secreted by women in various maladies, the same remarks apply only to a certain extent; for the human mammary secretion is so dependent on mental influences, that its composition appears readily affected. Vogel gives the following analysis of milk derived from a woman suffering from hysteria, the sample being taken directly after the attack:

Deveux found the milk of a woman who suffered from nervous attacks, when taken in the seizure, to be a transparent viscid secretion like albumen. J. F. Simont examined the milk of a woman who was suffering from the effects of passion. The secretion was apparently the cause of violent convulsions and diarrhoea in an infant. The milk was acid, and had acquired a peculiar odour. and after a little time developed hydrogen sulphide; or, in other words, the milk had commenced to undergo lactic acid and putrefactive changes in the breast itself. Local affections of the breast, as might be anticipated, interfere with the healthy action of the milk-producing cells. For example, Schlossberger gives the following as the composition of a sample of milk taken from a woman whose breast was considerably enlarged; the fluid was white and thick, and without odour, specific gravity, 98 to 99 at 15°:

Fatty matter,

Lactine and extractives,

Casein,

Ash,

The fat fused at 33° and solidified at 26°.

* Crell's Chemische Annalen, vol. 1, p. 369.

Per cent.
8.54

75

8.74

41

+ J. F. Simon's "Animal Chemistry," Syd. Soc., 11, 58.

II. Cows' MILK.

§ 155. Aphthous Fever.-One of the few affections in which it is possible for the investigator to discover an abnormal condition of the milk, and even from the appearance of the fluid to know what particular malady the cow is suffering from, is "foot-andmouth disease," or "aphthous fever." This is a febrile, highly infectious disease, which has caused of late great ravages among our herds; its most obvious signs are ulcers on the mouth, feet, and teats. Unless the fever is high, the milk is secreted during the whole course of the disease. It presents different (one might almost say, opposite) appearances in different cases; in those where there are ulcers on the teat, either externally or just inside, the pus from these ulcers mixes with the milk, and the analyst finds a high fatty residue, from which cholesterin, nuclein, lecithin, and milk-fat may be separated. If, on the contrary, there are no ulcers and no local affection of the udder, the milk in the more severe cases may be deficient in solids, and especially in milk-fat; nor does it recover its normal composition until about the seventh and eighth days, when the cow begins to improve.

A special micro-organism is, according to Klein, always to be found associated with aphthous fever, it is a micrococcus, which either occurs singly, as dumb bells or as streptococci, the chains of the streptococcus sometimes grow to a considerable length. The individual elements of the diplococci and streptococci are spherical, and have an average measurement of 0006 to 0008 mm. The micro-organism is readily cultivated in nutrient gelatin, agar-agar or broth; it grows slowly in sterilised milk, the milk remaining fluid. Milk, according to Klein, preserves the micro-organism in a wonderful manner; infected milk kept months in tubes still yielded successful cultures. If the local affection is at all severe, blood-cells, and occasionally a considerable quantity of blood may be found in such milk.

Mammitis.-This disease, as its name implies, signifies an acute inflammation of the mammæ. Theoretically, milk secreted by an inflamed organ should be altered much in quality; but, in the case of a heifer suffering from this disease, milk taken the second day after calving did not appear to differ essentially, either in microscopical appearances or in chemical composition, from normal milk. Its specific gravity was 10362, and the composition of the solids in 100 parts was as follows:

*Fifteenth Annual Rep. Loc. Gov. Bd., supplement containing report of Med. Officer for 1885.

Parturient Apoplexy.-A Cow suffering from Parturient Apoplexy; Pulse Imperceptible; Temperature 99°4 F. Third day after calving.

Specific gravity, 1037. Reaction feebly alkaline.

In 100 cc.

3.750

4.025

1.145

1.38)*

0.980

0.102

Urea was absent; there was much lactochrome. No abnormal elements detected by a microscopical examination.

The Milk of a Cow suffering from Pneumonia fourteen days after Calving. Pulse 82, Temperature 102°·4 F.

This is the only milk in which the writer found an estimable quantity of cholesterin. The microscopical results were negative.

At the time of the analysis the compound nature of the mercury precipitate was not known.

Phthisis.-A Cow, five years old, with Extensive Tubercular Deposit in Right lung. The Dam was also scrofulous.

A careful microscopical examination could detect no abnormal elements.

Phthisis.-A Cow, two years old, in an advanced stage of Phthisis.

The entire amount the cow yielded in January was 1 gallon; the amount sent for analysis was a fractional part of the whole.

A Sample of Milk drawn from an Udder actually Infiltrated with Tubercular Deposit.

It was

The whole quantity of the fluid did not exceed 70 cc. of a dirty amber colour, with the casein partially separating. A microscopical examination showed very few fat globules, and the following abnormal elements:

1. Clusters of oval or round granular cells, for the most part 0005 inch in diameter, with a well-marked oval nucleus.

2. Granular masses, irregular in shape, varying in size from about 0.0006 inch to ten or twelve times that size.

3. Granular rounded bodies, stained brilliantly by magenta or carmine.

This, then, is phthisical milk in its most intense form, and one never likely to be found in commerce, but admixture of such a fluid with genuine milk is possible.

It is essentially an albuminous serum, containing urea, common salt, and just sufficient casein and milk-sugar to show its origin from a much-diseased milk gland.*

Local Affection of the Udder.-Milk from a Heifer two days after calving, suffering from Retention of Fetal Membrane, a portion of the Udder much inflamed.

The milk was pink in colour, and contained about a twentieth of its bulk in blood; it was perfectly fresh when examined, but rapidly putrefied. The blood was separated by subsidence as much as possible. The reaction was feebly acid:

Possibly the tubercle bacillus will be found in such secretions; at the time of the analysis of the above, Koch had not published his researches. Good directions for the staining of these bacilli are given in Gibbes' Practical Histology. London, 1883.