U Colonel Sir Almroth E. Wright [March 9, 



surface in newly formed vessels a very aljundant blood supply. All 

 this is protection a2:ainst massive microbic invasion from the surface : 

 against the wound taking cold : and against erosive digestion. In 

 short, there is with an infected granulating surface much less danger 

 of a set-back than with an infected naked tissue surface. 



The Natural History of the Wound with a Naked Tissue Surface 

 Left to Itself 



Let us consider the natural history of the untreated wound with 

 an infected naked tissue surface. I will take the case of an open 

 shell wound left without treatment. According as it is wet or 

 dry the evolution of this wound will be entirely different. Let us 

 suppose that it is allowed to dry. Under the original dry dressing 

 the blood and lymph flow from the surface will gradually stanch, and 

 we shall then have a naked tissue surface with a coating of coagulated 

 blood and lymph. In this will be incorporated elements of 

 moribund tissue, other elements of foreign matter, and always a 

 certain number of microbes. Little by little the coating of coagulated 

 blood and lymph upon the surface of the original wound, or of the 

 surgeon's incisions, will dry up, and by that the capillary circulation 

 will be closed down. And all the while the serophytic microbes will 

 be proHferating. As a result of all this the superficial tissues will die, 

 and become gangrenous, and the originally clean naked tissue-surface 

 will gradually be transformed into a dry, greenish-black, excessively 

 foetid, slough-covered surface pullulating with microbic growth.* 

 Under the sloughs will then be formed infected dead spaces, and 

 from these the infection— I am here thinking in particular of a gan- 

 grene infection- will invade the neighbouring live spaces, converting 

 these in their turn into dead spaces until we have to cope with large 

 areas of gangrene and a general intoxication. 



That, of course, will happen only with very heavy infection or 

 extreme physiological deterioration. With lighter infection or less 

 adverse physiological conditions the invaded organism will have 

 recourse to measures of defence. Gradually the superficial sloughs 

 and gangrenous portions of the deeper tissues will l)e demarcated and 

 then amputated from tlie living tissues — the amputating agent being, 

 no douljt, the tryptic ferment in the dead spaces. And at the same 

 time there will have been organised in the living tissues some little 

 way back a defensive front built up on tlie same plan as a granu- 

 lating surface. 



Let me now tell you also what will happen if the infected surface 



* Let us note in connexion with this that the albuminous substances of 

 our tissues, wlien no longer ])athed in lymph, are immediately degraded to the 

 rank of unprotected native albumens. 



