MICROCOCCUS AUREUS. 269 



inflammations. As it is almost ubiquitous, it is a source 

 of continuous annoyance to 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 suppu- 

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

 that these conditions can be reproduced in lower ani- 

 mals. Its subcutaneous introduction into their tissues 

 does not always result in abscess-formation, and when it 

 does there seems to have been some coincident interfer- 

 ence with the circulation and nutrition of these tissues 

 which renders them less able to resist its inroads. When 

 introduced into the great serous cavities of the lower 

 animals its presence is likewise not always accompanied 

 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 intestines, large quantities of bouillon cult- 

 ures or watery suspensions of this organism may be, 

 and repeatedly have been introduced into the peritoneum 

 without the slightest injury to the animal. On the con- 

 trary, if some substance which acts as a direct irritant 

 to the intestines such, for example, as a small bit of 

 potato upon which the organisms are growing be at 

 the same time introduced, or the intestines be mechani- 

 cally injured, so that there is a disturbance in their cir- 

 culation, then the introduction of these organisms is 

 promptly followed by acute and fatal peritonitis. (Hal- 

 sted. 1 ) 



On the other hand, the results which follow their in- 

 troduction into the circulation are practically constant. 



1 Halsted : The Johns Hopkins Hospital Reports. Report in Sur- 

 gery, No. 1, 1891, vol. ii. No. 5, pp. 301-303. 



