CH. ix] OF TRANSMUTATION 135 



hastening its evacuation, would bring about the subsequent 

 appearance of these organisms in the faeces. 



C. The author's experiments. 



The following experiments were suggested to the writer 

 by Professor F. A. Bainbridge as likely to throw some further 

 light on this aspect of the question and were carried out at the 

 Lister Institute under his kind supervision. 



Experiment /. 24 healthy guineapigs were chosen and 12 

 of these were confined in 3 cages. On August 13th one of the 

 four guineapigs in each cage was removed and given in its 

 food 1 c.c. of a 48 hours' broth culture of B. enteritidis 

 Gaertner. Every precaution was taken to prevent, as far as 

 possible, any external contamination of the guineapigs with 

 the food and they were then returned to their respective 

 cages. This culture of B. Gaertner was made from a labo- 

 ratory strain the agglutination reactions of which had been 

 repeatedly tested and had been found to be constant. 



A bacteriological examination of the faeces of the 12 

 guineapigs was made subsequently on three occasions, namely 

 on August 23rd, September 19th and October 9th bacilli of 

 the paratyphoid group being identified by agglutination tests. 

 During this period each cage was kept separate from the 

 others and none of the guineapigs were removed from their 

 cages except for the necessary examination on the three 

 dates mentioned. Up to the time of the first examination on 

 August 23rd all the guineapigs remained well, but subse- 

 quently three of them died and the remainder exhibited 

 varying degrees of malaise and intestinal disturbance. The 

 following scheme shows the type of organism found in the 

 faeces at each examination. 



N.B. Guineapig No. 1 in each cage was given 1 c.c. of a 

 broth culture of B. enteritidis Gaertner on August 13th. " " 

 indicates that neither the Gaertner nor the Aertryck type of 

 organism was isolated. 



The faeces of the remaining 12 guineapigs, which had 

 been kept quite apart from the others, were carefully investi- 



