INFECTIOUS DISEASES AND MICROBES, ETC. 247 



animals. The animals were killed after several 

 months, and their organs had developed tubercles 

 containing the characteristic bacilli. (b) Swallowing, 

 or enteric infection, is a means of introducing the 

 tubercular virus into the animal economy. Babbits, 

 guinea-pigs, fowls, pigs, etc., become tubercular when 

 fed upon tubercular tissues, sputum, saliva, milk, 

 pure cultivations of the tubercle bacilli, etc. Klebs, 

 Arloing, Chauveau, Villemin, Gerlach, Baumgarten, 

 and others have shown, by direct experiment, that 

 the milk, flesh, etc., ' from cattle affected with tuber- 

 culosis would, when introduced alone or along with 

 other food into the alimentary canal of rabbits, 

 etc., give rise to tuberculosis in the pharynx, in the 

 lymphatic glands of the neck, the stomach, intestine, 

 omentum, liver, and spleen, and then, later, in other 

 organs.' Many authorities state that the flesh of 

 tuberculous animals (cattle, fowls, pigs, etc.) give 

 rise to tuberculosis in human beings. On the other 

 hand, there are authorities which state that there 

 is not much danger of human beings contracting 

 tuberculosis from eating meat from tuberculous 

 cattle; but it is a unanimous opinion among all 

 competent authorities that the milk of tuberculous 

 cows is a source of great danger to human beings 

 often giving rise to tuberculosis, especially in chil- 

 dren. It should be borne in mind that 'boiling always 

 destroys the virulence, even when the milk contains 

 bacilli, which is the case when the udder of the 

 affected cow is itself tuberculous ;' and the risk of in- 

 fection is greatly diminished, if not abolished, when 

 meat from tuberculous cattle is thoroughly cooked. 



