MICROCOCCUS TETRAGENUS. 329 



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 alteration can be seen in the organs of animals that 

 have died as a result of inoculation with miorocoocus 

 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 this disease, results in a re- 

 production of the conditions found in the dead animal 

 from which the tissues or cultures were obtained. 



It sometimes happens that in guinea-pigs which have 

 been inoculated with this organism local pus-formations 

 iL'Sult, instead of a general septicaemia. The organisms 

 will then be found in the pus-cavity. 



