ILLUSTRATING THE ANTISEPTIC SYSTEM OF TREATMENT 147 



taught that, if you do but apply carbohc acid freely to a wound, you will prevent 

 suppuration ; whereas I have all along pointed out that carbolic acid, being 

 a stimulating substance, will itself induce suppuration by long-continued action 

 on the tissues.^ 



[The facts observed in developing the antiseptic system have thrown great 

 light upon the causes which determine the occurrence of suppuration ; and 

 the subject is of such great practical importance that it may be well to take 

 this opportunity of giving definite expression to the conclusions to which I have 

 been led. It fell to my lot several years ago to establish, as the result of an 

 experimental inquiry, that the tissues of the living body are liable to a temporary- 

 impairment or suspension of vital energy as the result of extreme irritation ; 

 and that this condition, which appears to be the essence of intense inflammation, 

 may be brought about in two totally distinct ways — viz. either by the direct 

 operation of a noxious agent upon the tissues, or indirectly through the medium 

 of the nervous system.^ The same law appears to hold with regard to the causes 

 of the exaggerated but feeble cell-development which results from the continued 

 action on the tissues of some abnormal stimulus in a less intense form, giving 

 rise, according to its degree, to the various phenomena of inflammator\' hyper- 

 trophy, granulation, and suppuration ; the pus-cells being the extreme of 

 excess of quantity and impairment of quality in the product of abnormally 

 excited nutrition. Thus the causes of suppuration divide themselves into two 

 great groups : first, those that operate through the nervous system, or, in other 

 words, the inflammatory class, of which the common abscess presents a typical 

 example ; and, secondly, noxious agents or stimuli acting directly on the tissues. 

 The latter group are, practically speaking, stimulating salts, or chemical stimuli. 

 These are best studied in the behaviour of a healing ulcer under difterent 

 kinds of treatment. Small granulating sores sometimes heal by scabbing ; and 

 when the surface is thus protected by a crust of dried discharge from the in- 

 fluence of external agency, there is no further effusion either of pus or serum. 

 This is of itself sufficient evidence that granulations have no inherent tendency- 

 to form pus (or, as is sometimes absurdly said, to secrete it), but only do so 

 when stimulated. The same thing is equally clearly shown by the well-known 

 fact that two granulating surfaces will coalesce when placed in contact with 

 each other. This coalescence would be impossible if they continued to sup- 

 purate ; and their juxtaposition could oppose no obstacle to pus-formation if 

 they had any innate disposition to it. But their mutual contact excludes the 

 operation of external agents upon them ; being freed from stimulation, they 



' Sec pp. 6, 78 of this volume. 



* ' On the Early Stages of Inilamniatioii.' — PIti/. Tiaiis., 1S5.S (rcprintol in vol. i, p. J09). 



