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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



duced, the exudation liquid of which is found 

 after twenty-four hours to be charged with Bac- 

 teria. . . . Other chemical agents," he adds, " will 

 lead to the same results, and always under con- 

 ditions which preclude the possibility of the intro- 

 duction of any infecting matter from without." 



Elsewhere ' the same investigator refers to 

 experiments which were made about the same 

 time, in order to throw light upon the cause of 

 the appearance of Bacteria in certain peritoneal 

 exudations, and to ascertain whether or not their 

 presence was to be considered as " a mere result 

 of the intensity of the peritonitis." He says: 

 " To determine this, experiments were made 

 during the following month (May, 1871), which 

 consisted in inducing intense peritonitis by the 

 injection, not of exudation liquids, but of chem- 

 ical irritants, particularly dilute ammonia and 

 concentrated solution of iodine in hydriodic acid. 

 As regards the ammonia, precautions were taken 

 to guard against contamination by boiling and 

 cooling the liquids as well as the implements to 

 be used immediately before injection. In the 

 case of the iodine solution this was, of course, 

 unnecessary. In every instance it was found 

 that the exudation liquids, collected from twenty- 

 four to forty-eight hours after injection, were 

 charged with Bacteria, whence it appeared prob- 

 able that the existence of these organisms was 

 dependent, not on the nature of the exciting liquid 

 by which the inflammation was induced, but on 

 the intensity of the inflammation itself." 



From the various evidence more or less fully 

 referred to in the present section it seems to me 

 legitimate to conclude : 



1. That if we are to be guided by the anal- 

 ogy now dwelt upon as existing between fermen- 

 tation and zymosis, it would be perfectly certain 

 that the latter process can originate de novo — 

 that is, under the influence of certain general or 

 special conditions, and where specific contagia of 

 any kind are at first absent, though they subse- 

 quently appear as results or concomitant products. 

 So that an exclusive theory of " contagion," as 



> " Reports of the Medical Officer of the Privy Coun- 

 cil," etc., new series, No. vi., 1815, p. 57. 



the only present cause of communicable diseases, 

 is not supported by experimental evidence. 



2. That some contagia are mere not-living 

 chemical principles, though others may be living 

 units. 



3. That even in the latter case, if the pri- 

 mary contagious action be really due to the 

 living units and not to the media in which they 

 are found, such primary action is probably de- 

 pendent rather upon the chemical changes or 

 "contact actions" which they are capable of set- 

 ting up than upon their mere growth and vege- 

 tative multiplication. 



4. That where we have to do with a true 

 living contagium (whether pus -corpuscle or 

 ferment-organism), the primary changes which it 

 incites are probably of a nature to engender 

 (either in the fluids or from the tissue-elements of 

 the part) bodies similar to itself, so that the in- 

 fected part speedily swarms therewith. When 

 pus from a certain fecus of inflammation comes 

 into contact with a healthy conjunctiva, and 

 therein excites a contagious form of inflammation, 

 no one adopts the absurd notion that all the pus- 

 corpuscles in this second inflammatory focus are 

 the lineal descendants of those which acted as the 

 contagium ; and the mode of action may be al- 

 together similar when matter containing Bacilli, 

 by coming into contact with a wounded surface, 

 gives rise to splenic fever and the appearance of 

 such organisms all through the body. The old 

 notion about the excessive self-multiplication of 

 the original contagium is probably altogether er- 

 roneous. 



Thus all the distinctive positions of those who 

 advocate a belief in -the so-called " Germ-Theory 

 of Disease," or rely upon the exclusive doctrine 

 of a " Contagium Vivum," seem to be absolutely 

 broken down and refuted. We may give that 

 attention to the appearance and development of 

 independent organisms in association with morbid 

 processes which the importance of their presence 

 demands, but we must regard them as concom- 

 itant products, and not at all, or except to an 

 extremely limited extent, as causes of those local 

 and general diseases with which they are insepa- 

 rably linked. 





