ON THE ACTION OF CERTAIN BACTERIA 9 



Microscopically — 



Nothing definite was seen in smears. 



Cultures of the heart-blood on agar gave numerous grey, circular 

 smooth colonies which, on detailed examination, proved to be of the type 

 of B. enteritidis. 

 Animal test — 



The spleen of this rat was rubbed into the shaved belly of a guinea- 

 pig, which, however, remained healthy. 



III. — Mus decunnanus brought to the laboratory dead. 



Naked-eye appearances — 



Putrid ; organs discoloured ; no enlarged glands. 

 Microscopically — 



Preparations of the spleen and heart-blood showed some bipolar 

 organisms and many putrefactive bacteria. 

 Animal test — 



The spleen was rubbed cutaneously into a guinea-pig weighing 180 

 grammes. No decrease of weight occurred, but on the tenth day the 

 inguinal glands were slightly enlarged. At the end of a fortnight the 

 animal was chloroformed to death, and the following appearances 

 noted : — The left inguinal gland was somewhat enlarged, but showed no 

 signs of congestion ; the pelvic glands were also larger than normal. 

 There was a very slight local reaction. The spleen was somewhat 

 enlarged, and contained a few grey nodules. 



Microscopically — 



Preparations from the heart-blood and spleen showed no bacilli. 

 A culture of the bubo yielded a pure growth of Gaertner's bacillus. 



IV. — Liver of a Mus decumanus dead of a natural infection of 



Plague. 



The liver of a mus decumanus, dead of a natural infection of plague, 

 was covered with small grey nodules, in which fairly numerous plague 

 bacilli were found, on microscopical examination. It was rubbed into 



(295) 



