158 OMENTAL PLAGUE chap. 



stomach during digestion. I suspected that if B. pestis 

 could reach the small intestine unscathed — i.e. in a living 

 state — its power of multiplication would not only not be 

 interfered with, but that the alkaline condition there 

 might help it. A good parallel illustration is to hand in 

 the case of the bacillus of fowl cholera, viz. a microbe 

 which manifests its activities in the small intestine of that 

 bird, this being the organ principally affected by the 

 disease. It is extremely difficult to produce in the 

 laboratory a positive result by feeding fowls or rabbits — 

 both highly susceptible to inoculation — with culture of 

 the bacillus of fowl cholera. Nevertheless, it is notorious 

 that when once the disease is introduced into a poultry 

 farm it rapidly spreads, and that it can do so obviously 

 only by means of matter escaping from the alimentary 

 canal of the fowls ; the droppings of a diseased fowl 

 teeming with the specific microbe infecting the soil, and 

 consequently the food distributed on such soil. There 

 must, therefore, exist here conditions which essentially 

 differ from those in the laboratory experiment ; and it is 

 reasonable to suppose that the contagium mixed with the 

 soil and food is better secured against the action of the 

 gastric juice than when mixed as a broth culture with 

 food. It has hence occurred to me that it might be 

 possible to obtain greater success in plague-feeding experi- 

 ments by first protecting the contagium (B. pestis) by 

 drying it along with the food, or by administering it with 

 the food in such a state that some of it at any rate might 

 pass unscathed through the stomach. 



Experiment 1. — As already mentioned, I have made a 

 number of experiments in feeding guinea-pigs, rats, and 

 mice with virulent cultures of B. pestis (emulsion of 



