630 THE ENTEROCOCCUS 



majority of the organisms have been retained on the filter, the enterococcus 

 being almost the only species which has passed through. 



(b) Sow a trace of the stool in broth, aspirate the liquid into a Roux's 

 pipette and incubate at 37 C. for 24 hours in vacua ; then sow a number of 

 agar-slope tubes with the contents of the pipette after diluting the latter in 

 sterile broth. After incubating the agar tubes for 24 hours at 37 C. numerous 

 colonies of the enterococcus are seen ; other organisms are few in number. 



C. The virulence of the enterococcus should be tested by inoculating mice 

 and rabbits with 24 hour old broth cultures. 



D. The identification of the organism should be based upon a consideration 

 of all of the following points : 



1. The pleomorphism of the micro-organism : in pathological exudates 

 and in mouse's blood it has the appearance of the pneumococcus, in cultures 

 a few days old it resembles the streptococcus. 



2. The growth on gelatin at 20 C. 



3. The minimal amount of growth in liquid serum. 



4. The prolonged vitality of the organism. 



5. The fact that in many cases it must be grown anaerobically before it 

 will grow under aerobic conditions. 



