SUPPURATION. 221 



It is not motile, and being of the family of micro- 

 cocci, does not form endogenous spores. It possesses, 

 however, a marked resistance toward detrimental 

 agencies. 



In bouillon it causes a diffuse clouding, and after a 

 time presents a yellow sedimentation. 



This organism is the commonest of the pathogenic 

 bacteria with which we shall meet. It is the staphylo- 

 coccus pyogenes aureus, and is the organism most 

 frequently concerned in the production of acute, cir- 

 cumscribed, suppurative inflammations. It is almost 

 everywhere present, and is the organism most dreaded 

 by the surgeon. 



In studying its effects upon lower animals a number 

 of points are to be remembered. While it is the etio- 

 logical factor in the production of most of the suppura- 

 tive processes in man, still it is with no little difficulty 

 that these conditions can be reproduced in the lower 

 animals. Its subcutaneous introduction into their tis- 

 sues does not always result in abscess-formation, and 

 when it does, there seems to have been some coincident 

 interference with the circulation in these tissues which 

 renders them less able to resist its inroads. When 

 introduced ' into the great serous cavities of the lower 

 animals it is not always followed by the production of 

 inflammation. If the abdominal cavity of a dog, for 

 example, be carefully opened so as to make as slight a 

 wound as possible, and no injury be done to the intes- 

 tines, large quantities of bouillon cultures or watery 

 suspensions of this organism may, and repeatedly have 

 been introduced into the peritoneum without the slight- 

 est injury to the animal. On the contrary, if some 

 substance which acts as a direct irritant to the intes- 



