A cow affected with long-standing, advanced tuberculo:-is. 

 with large tuberculous svellings in the udder. A year before 

 the picture was taken the cow was discovered to have udder tu- 

 berculosis. This discovery was made by injecting some of her 

 milk into guinea pigs; there was nothing in the appearance or 

 external condition of the udder at first to show, that it was dis- 

 eased. How very dangerous such cows are may be judged from 

 the fact that calves that are permitted to drink milk from tuber- 

 culous udders only a single time are almost certain to have tu- 

 berculosis. A small amount of milk from cows like those in 

 the above picture and in figure 4 mixed with the milk of other 

 cows will make the wholp of it dangerous for both persons and 

 lower animals. 



