Disease Bacteria in Milk. 79 



factious qualities. In the early stages of the disease, the 

 milk appears perfectly normal; as the disease progresses 

 the milk assumes a watery appearance and changes in 

 color. A diseased condition of the udder can usually be 

 diagnosed where a hard, painless swelling of the udder 

 occurs that is confined to one quarter. Udder inflamma- 

 tions other than tubercular are generally accompanied 

 with pain. Milk from animals having udder tuberculo- 

 sis should be unconditionally rejected for food purposes. 



Woodhead 1 found in fourteen out of nineteen cases 

 that milk from a tuberculous animal or the sediment 

 from it was sufficiently infectious to produce the disease 

 in guinea-pigs inoculated with small quantities of it. 



The writer 2 found one case in which a single cc. of 

 milk from a diseased animal sufficed to kill a rabbit in- 

 oculated with it. In this same case, the bacilli were also 

 demonstrated microscopically in the milk. 



Sometimes the udder contains tubercle bacilli and still 

 does not show any external symptoms of the disease. 

 Bang 3 , Ernst 4 , and others have demonstrated that in 

 quite a percentage of animals with apparently healthy 

 udders, the milk possesses infectious properties. 



Where the disease is localized in the lungs, the danger 

 from the milk is probably but slight, but it is often im- 

 possible to determine the exact condition of the disease 

 in the animal. Even where the disease is local there is 

 a danger that a previous chronic condition may suddenly 

 become acute. 



With adults in normal health, the danger from an in- 

 fected milk-supply is undoubtedly greatly minimized, as 



1 Woodhead, Trans. 7th Intern. Hyg. Cong., London, 1891. 

 8 Russell, llth Kept. Wis. Expt. Stat., p. 196, 1894. 

 8 Bang, Cong, for Tuberculosis, 1888, p. 70. 

 4 Ernst, Hatch Expt. Stat., Bull. 8, 1890. 



