542 EXPERIMENTAL RESEARCHES WITH CHICKEN-CHOLERA MICROBES, 



cholera," all inside burrows, whereas thirty-two perished from causes 

 which had nothing in common with that disease.* 



The way in which these thirty-six rabbits, which died out of the 

 fifty, were examined, in order to see whether chicken-cholera bacteria 

 had found their way into them or not, was not the same each time. 



Twenty-two were at once subjected to a full examination ; for that 

 purpose they were taken out of the enclosure soon after their death. 

 Besides noting the condition of the organs, a microscopical examination 

 of blood was made. In sixteen cases liver-blood, in two cases liver- 

 and heart-blood, in two cases heart-blood only was examined ; in the 

 latter two instances the liver being unsuitable. From two rabbits 

 found dead inside a burrow, February 28th, and being in an advanced 

 state of decomposition, a sample each of coagulated heart blood was 

 inoculated into a medium-sized rabbit. Of the twenty-two rabbits 

 thus examined, only one (found inside burrow, February 16th) was 

 proved to have taken "chicken-cholera," while in the others neither 

 the autopsy, nor the microscopical examination of blood, warranted the 

 same verdict. 



From the remaining fourteen dead rabbits, while they were lying 

 about, some liver-substance was taken (in the manner described 

 previouslv), of which cover-glass preparations were made for micro- 

 scopical examination. Three times a positive result was obtained* 

 inasmuch as the typical bacteria of chicken-cholera, and only these, 

 were present in large numbers. The three respective rabbits, which 

 also by their outward appearance indicated death from "chicken- 

 cholera," were left, where they died, until the close of the experiment. 

 A subsequent post-mortem examination (including microscopic exami- 

 nation of blood, seven times) of the eleven remaining rabbits, in sampJes 

 of liver of which the microbes of chicken-cholera had not been found, 

 confirmed the negative result arrived at previously. 



To return once more to the four originally uninfected rabbits which 

 subsequently succumbed to " chicken-cholera," I am confident that 

 the germs of this disease could not have been supplied to those four 

 but by intentionally infected rabbits placed in the disease-division. 

 Not only was the greatest care taken in eliminating any possibility 

 of carrying infectious material among the rabbits, through food or 



* Of these thirtj'-two died ;— within the first week (12th-19th Februarj'), four ; within the 

 second (up to the 26th February), nineteen, of which six found dead on one daj' (February 

 23rd), and nine on another (February 20th); within the third (last) week (up to 5th 

 March), nine. 



