SOURCES OF INFECTION IN THE STABLE. 45 



that one of the reasons for the wide distribution of tuber- 

 culosis may be sought here.* All abnormal milk ought to be 

 removed from the stable and destroyed as soon as possible. 



Milk from Tuberculous Cows. The most common form 

 of diseased milk with us, which is abnormal when drawn 

 from the udder, is that from tuberculous cows. Such milk 

 should not be used without being freed from its infectious 

 qualities, above all where tuberculosis of the udder is pres- 

 ent. In the first stages of tuberculosis it is very hard to 

 prove whether the milk has an abnormal composition or 

 not without delicate bacteriological examinations; it still 

 has the color and appearance of ordinary milk, and the 

 number of tubercle bacilli in the same is comparatively 

 small. But as the disease develops, the abnormal condi- 

 tion of the milk can more easily be discovered with the 

 naked eye. Even when the disease is in its earlier stages 

 the milk assumes a somewhat yellowish color. Later on it 

 grows thinner and less viscous, and a large number of 

 slimy, cheese-like lumps may be discovered in the same. 

 The color finally turns entirely yellowish brown. 



We are often able, even in the earlier stages of tubercu- 

 losis, to tell the abnormal condition of the milk from the 

 fact that such milk does not show an amphoteric reaction, 

 but is alkaline a feature which is of course the more char- 

 acteristic the farther the disease has progressed.! 



* Bang states (Bull. 4, Copenhagen experiment station, 1885, 22) 

 that at a Danish creamery where centrifuge slime was fed to swine, 

 all of these proved tuberculous, and warns against the use of slime 

 for this purpose without its being previously boiled or heated toward 

 the temperature of boiling water. The prevalence of tuberculosis 

 among swine in certain parts of Germany has been attributed to this 

 system of feeding. (See Ftlhling's Landw. Zeitschrift 1893, p. 779 ; 

 Mikh-Zeitung, 1893, p. 672.) W. 



f Amphoteric Reaction of Milk. When drawn from the udder 



