200 BACTERIOLOGY. 



It grows both in the presence of and without oxygen. 



It is not motile. 



It stains readily with all the ordinary aniline dyes. 

 In tissues its presence is readily demonstrated by the 

 staining method of Gram. 



The grouping into fours is particularly well seen in 

 sections from the organs of animals dead of this form 

 of septicaemia. 



In such sections the organisms will always be found 

 within the capillaries. 



To the naked eye no alteration can be seen in the 

 organs of animals which have died as a result of inocu- 

 lation with the micrococcus tetragenus ; but micro- 

 scopic examination of cover-slip preparations from the 

 blood and viscera reveals the presence of the organisms 

 throughout the body especially is this true of prepara- 

 tions from the spleen. White mice and guinea-pigs are 

 susceptible to the disease. Gray mice, dogs, and rabbits 

 are not susceptible to this form of septicaemia. Subse- 

 quent inoculation of healthy animals with a drop of 

 blood, a bit of tissue, or a portion of a pure culture of 

 this organism from the body of an animal dead of the 

 disease, results in a reproduction of the conditions found 

 in the dead animal from which the tissues or cultures 

 were obtained. 



It sometimes occurs that in guinea-pigs which have 

 been inoculated with this organism, there results local 

 pus-formations instead of a general septicaemia. The 

 organisms will then be found in the pus-cavity. 



