Bull. 56, Hygienic Laboratory. 
17. THREE TUBERCULOUS COWS. 
The two on the right of the picture expel tubercle bacilli per rectum with their feces, and probably also with the material 
slobbered from their mouths during eating. Tubercle bacilli that are passed from the bowels of cows usually have their 
origin in the lung and throat, from which regions they are coughed into the mouth and swallowed. The visible condition of 
the cows shows nothing of their dangerous, tuberculous character. 
