milk,* obtained by squeezing the breasts of a newly-born infant-a male. In the course of a few days about a drachm was obtained. The following was the result of the analysis :

Sugar reaction strong.

The most complete analysis we yet possess of such milk is one by V. Gesner, which is given in the following table with other less perfect analyses :

Jolly and Filhol have recorded the case of an old lady, 75 years of age, who suckled successfully her grandchild. Similar instances have been recorded in dogs, and we fortunately possess one or two analyses which show that the fluid is certainly milk. Thus Filhol and Jolly give the following analysis of the milk derived from a bitch which had no connection with a male

The ash, on analysis, gave the following percentages in 100 parts

Chloride of sodium,

Chloride of potassium,

Calcic phosphate,
Sodic phosphate,

Sodic carbonate,

Traces of magnesic and sodic phosphates.

65.10

3.S8

27.75

1.40

1.87

Men before now have suckled children. Humboldt¶ relates the case of Francisco Lozano, whom he saw, and whose case he carefully investigated; and it appears established that this man did secrete from his breasts a nutrient fluid on which his infant son lived for many months, it is said, indeed, a whole year. The curious in such matters may consult the references given in the footnote for additional cases.

**

* Untersuchung der sogenannte Hexenmilch, J. Schlossberger, Annalen der Chemie u. Pharmacie, b. 87, 1852.

Jahrb. f. Kinderkrankheiten, N. F., Bd. ix., §160.

+ Schlossberger u. Hauff, Ann. Chem. Pharm., Bd. xcvj., p. 68.

§ Gabler u. Quevenne, op cit.

"Recherches sur le Lait," iii., Bruxelles, 1856.

Humboldt: "Voyage aux Régions Equinoxiales du Nouveau Continent." **Robert, Bishop of Cork: Letter concerning a Man who gave Suck to a Child, Phil. Trans., 1741, No. 461, t. xli., p. 813. Franklyn: "Narrative

Instances have also been known of a like kind among animals. Schlossberger has analysed the milk derived from a he-goat (Annalen der Chemie u. Pharmacie, 1844):

Milk-fat,

Caseine, with salts soluble in alcohol,

Sugar, with salts soluble in alcohol,

26.50

9.60

2.60

The ash was 782 per cent.-viz., 325 soluble in water, 457 insoluble. Occasionally the female mammæ after confinement has continued to yield milk, although the infant has either been dead or nourished otherwise. In such cases the milk deviates from its normal composition, and is, for the most part, highly albuminous. In a case of this kind recorded by Filhol and Joly, three analyses of the milk were made as follows, at different dates, about a week apart :

GENERAL EXAMINATION AND ANALYSIS OF MILK.

§ 137. The general examination and analysis of milk may be conveniently treated of under the following heads:

I. Microscopical examination of milk.

II. Analytical processes, more particularly for the purposes of the food-analyst.

A. General analysis of milk.

(a.) Specific gravity.

(b.) Total solids.

(c.) Extraction of milk-fat.

(d) Extraction of milk-sugar.

(e.) Albuminoids and ash.

of a Journey to the Shores of the Polar Sea," 1819, p. 157. Cobbold: Milk from the Male Mamma, Monthly Journal of Med. Science, 1854; t. xviii., p. 271. Morgagni: Adversaria Anatomica Omnia (V. Animadversio, i., p. 3).

Comptes Rendus, t. xxxvi., p. 571. 1853.

B. Various methods proposed for extracting the milk-fat. (1.) Solvents for fat.

(2.) Soxhlet's process.

(3.) Extraction by ether, acting on alkaline milk. C. Various other methods of milk analysis.

(1.) Drying in a vacuum.

(2.) Direct determination of the water.

(3.) Absorption of water by dehydrating agents.
(4.) Ritthausen's copper process.

(5.) Müller's process.

(6.) Clausnizer and A. Mayer's process.

III. Special details as to the more exhaustive and scientific analysis of milk.

(1.) Analysis of the milk-fat, and examination of the ethereal extract.

(2.) Extraction of the milk-sugar.

(3.) The ash.

(4.) Estimation of albumen.

(5.) Isolation of galactine.

(6.) Isolation of the principle precipitated by tannin. (7.) Estimation of urea.

(8.) Estimation of alcohol.

(9.) Volatile acids.

(10.) Estimation of the total acidity of milk, and estimation of lactic acid.

(11.) Detection of metals in milk.

I. MICROSCOPICAL EXAMINATION OF MILK.

§ 138. A mere chemical analysis is incomplete and insufficient in itself, and should in all cases be preceded or supplemented by a careful and painstaking microscopical examination. Normal milk, viewed under the microscope, presents for the most part a multitude of fat globules floating in a clear fluid. The globules of human milk measure in diameter from 002 to 005 mm.; those in the milk of the cow, from 00062 to 00039 inch [0016 to 01 mm.] These fat globules are of two kinds. By far the most numerous are evidently drops of fluid fat; but there are occasionally to be seen others which would appear to consist of solid fat, for they are rougher on the surface, and less soluble in ether, characteristics which they lose on warming, becoming like liquid-fat globules. In human milk, and, to a certain extent, in cows' milk, there are also as normal constituents, but in sparse quantity

(1.) Fatty drops having a half moon-shaped, finely granular substance;

(2.) Clear cells enclosing one or two fatty drops, and an eccentric nucleus;

(3.) Round clear bodies, easily coloured by eosin and picrocarmine. These last Heidenhain considers to be free nuclei.*

In the colostrum, or milk drawn the first few days after parturition, there are present other elements-viz., the socalled "colostrum cells." Some of these consist of a number of small and large fat globules, held together by a hyaline tissue or membrane, swelling on the addition of acetic acid or alkalies, and only slowly coloured by aniline red. There are other granular cells coloured at once by the same reagent. If the milk is taken fresh and warm, and a minute drop examined on a Strecker's warm stage,† and kept at a temperature of 38°, the corpuscles will exhibit amœboid movements, perfectly similar to those which have been noticed in the white corpuscles of the blood. Indeed, it is almost certain that the colostrum cells are no other than the white corpuscles of the blood, infiltrated with milk-fat, for Heidenhain, having injected into the dorsal lymph vessel of the frog a cc. of fresh milk, after 48 hours found the white corpuscles loaded with milk-fat, and in no respect distinguishable from colostrum. cells. When the milk has undergone any fermentation, the lactic ferment itself may be identified, and little lumps of caseine may be seen. These are mostly irregular and amorphous, but sometimes they have the appearance of flattened cylinders, and other shapes. In abnormal milk may be detected pus or blood, or sometimes both. If the pus is

derived from inflammations within the mammæ, and has been mixed with the milk before milking, the pus cells become infiltrated with milk-fat, and are difficult to distinguish from colostrum granules; but if derived from ulcers on the teats, they have the usual appearance of pus cells. The pus cells, like the colostrum cells, and the mucous corpuscles, are all different forms of white blood-corpuscles [leucocytes], and when placed on the warm stage exhibit amoeboid movements. Pus cells, as usually observed, are spheroidal, granular, and colourless, measuring from about 1-2500 to 1-3000th of an inch in diameter. On treatment with dilute acetic acid, the cell clears up, and shows two, three, or four nuclei. Blood, in small quantity, gives a pinkish

*R. Heidenhain: "Handbuch der Physiologie." Herausgegeben von Dr. L. Hermann. Leipzig, 1880.

+ In default of Strecker's stage, a plate of copper, having a central aperture and a thick straight wire, some inches in length, may be used. The plate is kept at the desired temperature through heating the wire by means of a spirit lamp.

colour to milk; if a large amount be present, it sinks to the bottom in red flocculent masses, which soon, from being deoxidised by the milk, acquire a tint varying from a red more or less dark, to a shade almost black. In small quantities reliance must be placed on the microscopic appearance of the blood-discs, which are wholly unlike any cell found in normal milk. The red blooddiscs of the cow are like those of the human subject-little circular, biconcave, flattened discs, measuring on an average 1-4000th part of an inch. Human blood-discs have an average diameter of 1.3500 inch. By the aid of the micro-spectroscope, the absorption-bands may also be seen. These are, in oxidised blood, two bands between D and E, the one close upon the red being narrower, darker, and better defined than the one nearer to the green; with deoxidised blood, only one band is seen, between D and E. On treating the blood with oxygen, or shaking it up with air, the two bands re-appear. In "blue" milks a peculiar fungus has been discovered, and in the milk from animals suffering from foot-and-mouth disease, certain special appearances have also been noted, which are described in the section treating of this disease.

II. ANALYTICAL PROCESSES MORE PARTICULARLY FOR THE PURPOSES OF THE FOOD-ANALYST.

§ 139. The early attempts at the analysis of milk have been already detailed.

One of the first accurate processes for the general analysis of milk which the author has been able to find, was published in 1853, by MM. Vernois and A. Becquerel.

A small quantity [30 grms.] was taken, dried, exhausted with ether, burnt up to an ash; the sugar obtained "à saccharimètre" from the whey, the caseine being first separated by coagulation by acetic acid, and then estimated by difference. This process was certainly capable of giving very fair and accurate results, and it is the more curious to note, how many English analysts, even very recently, employed erroneous and clumsy methods.

Mr. Wanklyn, by his work on milk analysis, revived the more accurate method of using comparatively small quantities for analysis, thus avoiding very considerable error, from the risk of large quantities decomposing by prolonged heating. He advocated the use of platinum dishes, and supported strongly the Comptes Rendus, t. 36, p. 187, 1853.

+ “Milk-Analysis." By J. A. Wanklyn. Lond. 1874.