66 Dairy Bacteriology. 



villages and public buildings will frequently contain 

 tubercle organisms. Some of the organisms in the air 

 find their way into the lungs, there to develop and pro- 

 duce consumption. The organisms in the air may be 

 deposited in the nasal passages and throat, and ulti- 

 mately find their way into the tissues of the body by 

 penetrating the walls of the throat or of the intestine. 

 It is probable that the tubercle bacilli thus introduced 

 may find their way to the lungs and there develop 

 without leaving any trace of their path. 



Food may also possibly serve as a medium of infec- 

 tion. The contamination of solid food from flies and 

 other sources is, of course, a possibility, but tuberculous 

 meat from cattle and swine is much more likely to oc- 

 cur, although it must be said that the processes of pre- 

 paring such food for use (roasting, frying, and boiling) 

 are sufficient to destroy the vitality of the causal or- 

 ganism. The fact that most food products of this char- 

 acter are now inspected renders this possibility less 

 likely to occur. 



Unquestionably, the likelihood of ingesting tubercle 

 organisms is much greater with milk than with any 

 other food supply, as milk is consumed usually in an 

 uncooked state, and as microscopic and physiologic 

 tests indicate that not infrequently milk from tuber- 

 culous animals contains these organisms. 



Distribution of the disease in animals. As practi- 

 cally any organ of the body may be affected with tuber- 

 culosis, it naturally follows that the lesions of this dis- 

 ease are widely distributed. The disease germ is intro- 

 duced, in the main, through the lymph and not the 

 blood system; consequently, in the initial stages the 

 evidence of tuberculosis is often comparatively slight, 



