FATJ-; (! Tri'.F.kri'.K BACILLI Orrsini-: TIIK ANIMAL BODY 



299 



nant" ; and on the other hand Chanssc- :! says, "Tuberculosis in 

 adult bo.vine is due to inhalation in 98 percent of the cases, if not 

 more ; in calves in about 90 percent, ingestion and congenital in- 

 fection being responsible for the remainder." Dr. Ravenel 115 , a 

 strong believer in ingestion as one of the important causes of 

 tuberculosis says, "One must take an impartial view of the whole 

 problem, and be willing to agree that both channels of infection 

 are open. In animals, however, the alimentary tract seems to be 

 a more common port of entry". 



At present, at least, both ways of infection should be consid- 

 ered very dangerous and every precaution taken to guard against 

 them. A brief summary of the literature concerning the length of 

 time that tubercle bacilli live in dried tuberculous material and 

 concerning the infectiousness of such material is given in Table 6. 



TABI,E 6 EFFECT OF DESICCATION OF TUBERCLE BACIU,I IN SPUTUM AND 



OTHER MATERIAL 



