er (Zeit. f. Hyg., 1902, 38:34) examined the statistics of
638 typhoid epidemics. He found 71 per cent. due to infected drinking
water, 17 per cent. to infected milk, and 3.5 per cent. caused by other
forms of food.

[115] Kitasato. Arb. a. d. Kais. Gesundheitsamte, 1:470.

[116] Simpson, London Practitioner, 1887, 39:144.

[117] Swithinbank and Newman, Bacteriology of Milk, p. 341.

[118] Schottelius and Ellerhorst. Milch Zeit., 1897, pp. 40 and 73.

[119] Baginsky, Hyg. Rund., 1895, p. 176.

[120] Gaffky, Deutsch. med. Wochen., 18:14.

[121] Fluegge. Zeit., f. Hyg., 17:272, 1894.

[122] Duval and Bassett, Studies from the Rockefeller Inst. for Med.
Research, 2:7, 1904.

[123] Zeit. f. physiol. Chemie, 10:146; 9 Intern. Hyg. Cong. (London),
1891, p. 118.

[124] Vaughan and Perkins, Arch. f. Hyg., 27:308.

[125] Newton and Wallace (Phila. Med. News, 1887, 50:570) report three
outbreaks at Long Branch, N. J., two of which occurred in summer hotels.

CHAPTER VI.

BACTERIA AND MILK SUPPLIES WITH ESPECIAL REFERENCE TO METHODS OF
PRESERVATION.

To the milk dealer or distributor, bacteria are more or less of a
detriment. None of the organisms that find their way into milk, nor the
by-products formed by their growth, improve the quality of milk
supplies. It is therefore especially desirable from the milk-dealer's
point of view that these changes should be held in abeyance as much as
possible. Then too, the possibility that milk may serve as a medium for
the dissemination of disease-breeding bacteria makes it advisable to
protect this food supply from all possible infection from suspicious
sources.

In considering, therefore, the relation of bacteria to general milk
supplies, the _economic_ and the _hygienic_ standpoints must be taken
into consideration. Ordinarily much more emphasis is laid upon the first
requirement. If the supply presents no abnormal feature as to taste,
odor and appearance, unfortunately but little attention is paid to the
possibility of infection by disease germs. The methods of control which
are applicable to general milk supplies are based on the following
foundations: (1) the exclusion of all bacterial life, as far as
practicable, at the time the milk is drawn, and the subsequent storage
of the same at temperatures unfavorable for the growth of the organisms
that do gain access; (2) the removal of the bacteria, wholly or in part,
after they have once gained access.

Until wi