84 THE GROUSE DISEASE chap. 



infection in fowls, pigeons, and rabbits. And the 

 virulence of the cultures, be they derived from fowl, 

 pigeon, or rabbit, is maintained unimpaired for an 

 unlimited number of sub-cultures in broth, gelatine, 

 or Agar, provided these be used when recent. I 

 have had sub-cultures which had been carried on 

 on gelatine for from several months to over two 

 years ; fresh broth sub - cultures started from them 

 proved always virulent. Fowls can be infected not 

 only by subcutaneous injection but also by feeding, 

 but the result is not by any means so certain ; since 

 some animals escape infection. As has been men- 

 tioned above, the intestinal contents teem with the 

 bacilli, and it is therefore justifiable to assume that 

 under natural conditions the food picked up from 

 the ground by the fowls becomes contaminated with 

 the microbes of the dejecta. Before concluding this 

 description, which is introduced here merely for the 

 sake of comparing this disease with the disease to 

 be described presently, viz. with the fowl enteritis, I 

 wish to mention two further points : — 



(i.) The enormous rapidity with which the microbe 

 multiplies in the rabbit. A rabbit of known weight 

 was inoculated with a drop of broth culture containing 

 about 20,000 bacilli ; the animal was dead with the 

 typical disease in 20 hours. The number of the bacilli 

 present in the heart's blood was then ascertained, and 



