136 Bureau of Farmeiis' Institutes. 



of living animals favorable for its multiplication. It tlierefore 

 does not grow as a saprophyte under ordinary circumstances. But 

 it Las been noted by Nocard and Koux that when it has been culti- 

 vated for a time in artificial media containing glycerin it may 

 grow in a plain bouillon of veal or chicken, in which media it fails 

 to develop when introduced directly from a culture originating 

 from the body of an infected animal. The human is omnivorous, 

 the bovine is herbivorous. The normal human pulse is about 72, 

 that of the ox 40 to 45. The normal temperature of the human is 

 98.6° F., that of cattle from 100° to 100.5° F. Thus the normal 

 temperature of the ox is equal to quite a fever in the human. I 

 am of the opinion that there is something in the human body 

 antagonistic to the favorable development of the tubercle bacillus 

 of the bovine, and there is in the body of the bovine a check to 

 the colonization of these animals by the bacilli from the human 

 species. Hordes of Hottentots transferred to the polar regions 

 would rapidly perish, yet the Eskimo thrives there. Sternberg 

 says : " A certain species of bacilli may be pathogenic for one 

 species and not for another. Thus the anthrax bacillus, which is 

 fatal to cattle, sheep, rabbits, guinea-pigs, and mice, does not kill 

 white rats. The bacillus of mouse septicaemia kills house mice, 

 but field mice are fully immune from its pathogenic effects. On 

 the other hand, the bacillus of glanders is fatal to field mice, but 

 not to house mice." Here is a distinction as finely drawn as that 

 which I have alleged as existing between man and the ox. 1 

 believe that the tubercle parasite of man has by its long existence 

 in that host acquired, as it were_, individual characteristics which 

 unfit it for life in the ox, and that the " micro-organism " of 

 tubercle, which for centuries has had its habitation in cattle, has 

 become practically specific to that class of animals. I am there- 

 fore persuaded that if the environment be changed in either direc- 

 tion the pathogenic power will be lost. I have read of cases of 

 accidental inoculation of the human from the bovine, and if they 

 have occurred they must be very rare, inasmuch as none have 

 come under the writer's observation, and probably no one has 

 had greater experience with tuberculosis in cattle. I am positive 



