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942 some 14,000 alumni. A new university hospital was to be completed in 1922 with accommodation for 600 patients, affording proper facilities for the teaching of medicine, and the first hospital con- trolled exclusively for the benefit of the people of the state. Four dormitories for women students were also erected during this period.

The income of the university in 1919-20 was $3,802,164. Of this amount $1,687,500 was derived from the state through the tax of three-eighths of a mill on every dollar of taxable property, $38,428 from the state lands originally granted by the Government for the support of the university, $682,445 from tuition, student fees, etc., and $659,250 from special appropriations and savings for the erection of buildings.

Over 12,000 graduates and students of the university were enlisted in the U.S. forces during the World War, of whom 231 lost their lives. This number included 2,747 students who were enrolled in the collegiate section of the Students' Army Training Corps during the fall of 1918. Pres. James Burrill Angell, upon his resignation in 1909, was succeeded by Harry Burns Hutchins, dean of the Law School, as acting president (1909-10) and president (1910-20). Pres. Hutchins resigned in 1920 and was succeeded by Marion Leroy Burton, who had been president of Smith College (1910-7) and of the university of Minnesota (1917-20).

See A Memorial of the Seventy-fifth Anniversary of the Founding of the University of Michigan (Ann Arbor, 1915) ; also Wilfred Shaw, The University of Michigan (New York, 1920) and A. L. Cross, " The University of Michigan and the Training of her Students for the War," Michigan History Magazine (Lansing, Jan. 1920).

(W. B. S.) MIDLETON, WILLIAM ST. JOHN FREMANTLE BRODRICK, (1856- ), English politician (see ), did not remain long out of Parliament after his defeat in the general election of 1906, as in the following year his father died, and he entered the House of Lords as pth viscount. He took a considerable share in the work of that House, and played an active part behind the scenes in Unionist politics, without returning to ministerial office. He was indeed perhaps the most conspicuous figure among the Unionist leaders who did not find a place in Mr. Asquith's Coalition Cabinet. He had meanwhile become specially prominent as leader of the southern Unionists of Ireland, in virtue of his position as a landowner in county Cork. In his opposition to the Home Rule bills, he was never willing to base himself mainly on the difficulties of Ulster, but constantly called attention to the necessity of protecting loyalists in the South and securing them from discriminating taxation. He was disquieted by the negotiations carried on in the summer of 1916 with the Irish leaders by Mr. Lloyd George on behalf of Mr. Asquith's Coalition Ministry, on the basis of excluding the six Ulster counties but bringing the Home Rule Act at once into effect in the rest of Ireland. In the Irish Convention, which was set up in the middle of 1917 and sat into the following year, he and a band of southern Unionists separated themselves from the Ulster standpoint, and showed themselves ready to concede a unitary Home Rule Government for Ireland, subject to provisions for safeguarding the minority of loyalists. At the beginning of 1920 he was created an earl.  MILK (see 18.451, 7.737). From time immemorial milk and milk products have been highly prized by man as a food, and Jewish, Egyptian, Greek and Roman literature contain numerous references to the use of milk and milk products. In earlier times the milk of nearly all the domestic animals was used for the food of man, and although at the present time the milk of the cow provides the main bulk of the world's dairy products, the milk from the ass, goat, mare, reindeer, camel, ewe, llama and zebra is still used in various parts of the world.

Milk consists of a watery intimate admixture of protein, fat, carbohydrate, and soluble inorganic constituents (the latter being usually referred to collectively as ash), the proportion and amount of these constituents varying according to the species

from which they are derived. The principal protein of milk is casein, a protein not found elsewhere in the body, and belonging to a group of proteins called phosphoproteins owing to the presence of combined phosphorus in the protein. Other pro- teins are present, namely, lactoglobulin and lactalbumin.

It was formerly believed that the proteins of milk were identi- cal with the proteins of blood serum, and that they found their way into the mammary secretion as a result of simple and direct transference from the blood stream. Recent chemical work on the structure of these proteins has not, however, confirmed this belief. Hartley (1914) analysed the proteins of serum by the method of Van Slyke; Crowther and Raistrick (1916) by the use of the same method analysed the corresponding proteins of milk and colostrum. Woodman (1921) investigated the optical behaviour of these proteins when dissolved in dilute alkali at a temperature of 37 C C. The results of these investigations indi- cate clearly that whereas the globulins of serum, colostrum and milk are one and the same protein, yet serum albumin and lactal- bumin are to be regarded as distinct chemical individuals. From this the conclusion must be drawn that a distinct mammary syn- thesis is necessary for lactalbumin as well as for caseinogen.

Fats occur in milk in the form of minute globules, there being millions present in each c.c. of milk. The average diameter of these globules varies from -01 mm. to -0016 mm. Milk fat dif- fers from body fat in that it contains a relatively large amount of olein and also in the fact that considerable quantities of fatty acids of low molecular weight are present. It is upon the pres- ence of the fatty acids in butter fat that one of the tests for the purity of butter fat depends. In addition to traces of other bodies, the milk fat carries with it varying amounts of colouring matter derived from the food eaten.

The carbohydrate present in milk consists of a sugar called lactose. This sugar is peculiar to milk, and it is owing to the fermentation of this sugar by bacteria with the formation of lactic acid that the souring of milk is due.

The table below gives the average composition of the milk of different mammals.

The differences shown in the table below indicate a very im- portant fact that the milk of the species is peculiarly adapted for the efficient nutrition of the young of that species. Especially is this the case with the inorganic constituents of the milk. It is this difference in composition that necessitates especial care in the use of cow's milk for the rearing of infants. Although the composition of milk varies considerably among individuals of the same species, the variation in the same individual is as a general rule very small, and, contrary to general opinion, is but slightly influenced by conditions of feeding.

Origin of Milk and Development of Mammary Gland. The first sign of development of the mammary gland in the embryo is the formation of a slightly thickened ridge or line called the mammary ridge. This is a slight thickening of the epidermis extending from the inguinal region to the axilla. This thickening becomes intensified in the areas in which eventually the mammary glands are situated, and little bud-like outgrowths of the epithelium extend into the under- lying connective tissue in these regions, forming the mammary ducts. These ducts give rise to the galactophorous or milk sinus and milk ducts, and eventually form the alveoli. The thickened epithelium forms the nipple, so that the fully developed mammary gland in the adult resembles a bunch of grapes bound together with fatty connective tissue.

At birth the mammary glands are alike in both sexes, and consist entirely of a few rudimentary ducts and nipple. During infancy very little growth takes place, although towards puberty consider- able deposition of fat takes place in the female in the vicinity of the nipple. At puberty in the female a certain amount of growth takes place, and occasionally a few alveoli, or milk-producing sacs, are

Woman

Cow

Buffalo

Goat

Ewe

Mare

Ass

Reindeer

Whale

Water Fat Protein .... Milk Sugar Salts

88-32 3-43 1-55 6-44 0-26

87-75 3-40 3-50 4-60 o-75

82-57 7-63 4-69 4-30 0-81

86-34

4-25 4-40 4-26 o-75

81-08 7-67 6-08 4-26 0-91

90-38

I-OO

1-98 6-28 0-36

90-30 1-30 i -80

6-2O

0-40

67-7 17-1 10-9

2-8

i-5

60-47 20-00 12-42

5-63

1-48

IOO-OO

IOO-OO

100-00

IOO-OO

IOO-OO

IOO-OO

IOO-OO

IOO-OO

IOO-OO

Specific Gravity

1-032

1-0315

i-33

I -033

1-038

1-034

1-033