under the skin, at various places, in different rabbits. In 

 no instance was suppuration or even adhesive. inflamma- 

 tion observed the capsules remained freely movable in 

 the subcutaneous tissue. After intervals varying from 

 two to fourteen days, when the incision wound was firmly 

 healed, the capsules were broken subcutaneously, by 

 force applied to the skin ; in every instance suppuration 

 followed in a few hours. An examination of the pus and 

 abscess walls revealed nothing that could be recognized 

 as bacteria. 



Chronic or cold abscesses may have a different etiol- 

 ogy their clinical history and appearances, and the fact 

 that they seldom cause pyaemia, would point to that con- 

 clusion. It is significant that of eighteen chronic ab- 

 scesses, Ogston employing the most approved tech- 

 nique could detect bacteria in but four, which were 

 consequent, moreover, upon erysipelas, typhoid fever, 

 pharyngitis, and pulmonary consumption, respectively ; 

 in the remaining fourteen, both microscope and attempts 

 at cultivation gave only negative results. Their absence 

 at the time of examination does not exclude the possi- 

 bility of their presence at an earlier period of the pro- 

 cess ; that they may have lost their vitality, and with it 

 their power to absorb the coloring agents. 



Suppuration must be regarded, then, as indicating the 

 presence of an element foreign to the living animal cells ; 

 which may be introduced directly, like the croton oil in 

 Councilman's experiment, or indirectly as an incident in 

 the life of various fungi. That a derangement, of cell- 

 nutrition, local gangrene, may by mechanical or chem- 

 ical irritation, without the presence of other organisms, 

 effect the same result, seems probable in view of clinical 

 experience, but is not yet experimentally proven. Prac- 

 tically, we may regard acute suppuration as proof of the 

 access of external irritant matter, organized or unorgan- 

 ized ; and clinically, we must agree with Cohnheim, that 

 suppuration not due to bacteria or other fungi is ex- 

 tremely rare. The comparative rarity of pus-formation 

 under the Lister dressing although this is, at best, an 



