f milk.

[128] Farrington, Journ. Amer. Chem. Soc., Sept., 1896.

[129] Hite, Bull. 58, West Va. Expt. Stat., 1899.

[130] Milch Zeit., 1895, No. 9.

[131] Ibid., 1897, No. 33.

[132] Bernstein, Milch Zeit., 1894, pp. 184, 200.

[133] Thoerner, Chem. Zeit., 18:845.

[134] Snyder, Chemistry of Dairying, p. 59.

[135] Doane and Price (Bull. 77, Md. Expt. Stat., Aug. 1901) give quite
a full resume of the work on this subject in connection with rather
extensive experiments made by them on feeding animals with raw,
pasteurized and sterilized milks.

[136] Rickets is a disease in which the bones lack sufficient mineral
matter to give them proper firmness. Marasmus is a condition in which
the ingested food seems to fail to nourish the body and gradual wasting
away occurs.

[137] De Man, Arch. f. Hyg., 1893, 18:133.

[138] Th. Smith, Journ. of Expt. Med., 1899, 4:217.

[139] Russell and Hastings, 17 Rept. Wis. Expt. Stat., 1900, p. 147.

[140] Russell and Hastings, 21 Rept. Ibid., 1904.

[141] Russell and Hastings, 18 Rept. Ibid., 1901.

[142] Russell, Bull. 44, Wis. Expt. Stat.

[143] Russell, 22 Wis. Expt. Stat. Rept., 1905, p. 232.

[144] Russell, 12 Wis. Expt. Stat. Rept., 1895, p. 160.

[145] De Schweinitz, Nat. Med. Rev., 1899, No. 11.

[146] Harding and Rogers. Bull. 182, N. Y. (Geneva) Expt. Stat., Dec.,
1899.

[147] Jensen, Milchkunde und Milch Hygiene, p. 132.

[148] 22 Wis. Expt. Stat. Rept., 1905, p. 236.

[149] Shockley, Thesis, Univ. of Wis., 1896.

[150] Marshall, Mich. Expt. Stat., Bull. 147, p. 47.

[151] Fleischmann, Landw. Versuchts Stat., 17:251.

[152] Babcock and Russell, Bull. 54, Wis. Expt. Stat., Aug. 1896.

CHAPTER VII.

BACTERIA AND BUTTER-MAKING.

In making butter from the butter fat in milk, it is necessary to
concentrate the fat globules into cream, preliminary to the churning
process. The cream may be raised by the gravity process or separated
from the milk by centrifugal action. In either case the bacteria that
are normally present in the milk differentiate themselves in varying
numbers in the cream and the skim-milk. The cream always contains per
cc. a great many more than the skim-milk, the reason for this being that
the bacteria are caught and held in the masses of fat globules, which,
on account of their lighter specific gravity, move toward the surface of
the milk or toward the interior of the separator bowl. This filtering
action of the fat globul