INFECTION WITH SARCINA TETRAGENA 423 



The transparent mucilaginous substance which is seen 

 to surround these organisms renders them coherent, so 

 that efforts to take up a portion of a colony from the agar- 

 agar or potato cultures result usually in drawing out fine, 

 silky threads, consisting of organisms imbedded in the 

 mucoid material. 



The organism grows best at from 35 to 38 C., but can 

 be cultivated at the ordinary room-temperature about 

 20 C. 



The growth under all conditions is slow. 



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 sec- 

 tions from the organs of animals dead of this form of septi- 

 cemia. In such sections the organisms will always be found 

 within the capillaries. 



INOCULATION INTO ANIMALS. To the naked eye no altera- 

 tion can be seen in the organs of animals that have died as 

 a result of inoculation with sarcina tetragena; 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 preparations 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 septicemia. 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 reproduction of 

 the conditions found in the dead animal from which the 

 tissues or cultures were obtained. 



