MICROCOCCUS TETRAGENUS. 265 



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. 



Inoculation into animals. To the naked eye no alter- 

 ation can be seen in the organs of animals that have 

 died as a result of inoculation with the micrococcus 

 tetragenus ; but microscopic examination of cover-slip 

 preparations from the blood and viscera reveals the 

 presence of the organisms throughout the body espe- 

 cially is this true of preparations from the spleen. 

 White mice and guinea-pigs are susceptible to the dis- 

 ease. Gray mice, dogs, and rabbits are not susceptible 

 to this form of septicaemia. Subsequent 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, result 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 result local 

 pus-formations instead of a general septicaemia. The 

 organisms will then be found in the pus-cavity. 



