566 BOARD OF AGRICULTURE. [Pub. Doc. 



of introducing the bacilli was chosen because it was likely to 

 furnish the most uniform conditions, and also because tuberculosis 

 of the organs of the chest is the most frequent form of disease 

 among cattle. 



Experiment I. — This, as stated above, was made in 1895, with 

 two cultures, one from an old bull, with advanced generalized 

 disease, involving also some of the bones, the other from a tuber- 

 culous animal probably infected from its tuberculous master. 



Two heifers were inoculated with these cultures, as described 

 above. The one receiving the bovine culture died in thirty-five 

 days, with miliary tuberculosis of the lungs and general tuber- 

 culosis disseminated throughout the body. The one receiving the 

 presumably human culture showed no signs of disease, and when 

 killed fiftj'-four days after inoculation, not even a local lesion 

 could be traced. 



Experiment II. — This experiment was carried out two years 

 later, in 1897, and included four head of cattle. The tubercle 

 bacilli were obtained from the following sources : — 



Sputum culture II,, from a rapid case of phthisis in New Bedford, 

 Mass. 



Sputum culture III., from a subsequently fatal case of phthisis in 

 Norwood, Mass. 



Bovine culture II., from an old cow slaughtered in Lawrence, Mass., 

 in which there was slight disease of the lungs and mediastinal glands 

 (specimens brought me hy Dr. Alexander Burr). 



Swine culture I., from swine living under a cow barn in Massachusetts 

 (specimens obtained by Dr. Austin Peters). This culture in every 

 way appeared identical Avith the bovine cultures, and this, together 

 ■with the fact that the swine were exposed to infection from cattle, led 

 me to assume that this was a bovine culture in origin. 



On May 1, 1897, these four cultures were injected into four 

 head of cattle. The total age of the cultures, or, in other woi'ds, 

 the total period of time during which they had been growing on 

 dog's serum, was as follows : — 



Sputum culture II., five months, nine days old, eighth transfer. 

 Sputum culture HI., two months, fifteen days old, fourth transfer. 

 Bovine culture II., five months, two days old, fifth transfer. 

 Swine culture I , eleven months, twenty-three days old, sixteenth 

 transfer. 



Assuming that tubercle bacilli become slowly weakened in 

 virulence by artificial cultivation, we should endeavor to use 

 cultures as fresh and of as nearly the same age as possible. This 



