THE GERM-THEORY OF DISEASE. 



311 



My urine and potash experiments will go far 

 to illustrate this difference in the weight of the 

 evidence in regard to the two questions. 



A " sterilized " fluid — that is, one which left 

 to itself would always remain pure — may be 

 caused to ferment by the addition of a certain 

 proportion of liquor potassae devoid of all living 

 things, especially if the influence of the potash 

 be favored by certain accessory physical condi- 

 tions. This fact is admitted by M. Pasteur him- 

 self. During the fermentation thus initiated, a 

 matter (ferment) appears and increases, which is 

 capable of spreading a similar process far and 

 wide in suitable media. 



But, on the strengh of the analogy upon which 

 the germ-theorists rely, we may find in such an ex- 

 periment a warrant for the belief that in a healthy 

 person, free from the contagium of typhoid fever 

 or any other of its class, certain kinds of ingesta 

 (solids or fluids), wholly free from all specific 

 poison may, with or without the favoring influ- 

 ence of other altered conditions, give rise to an 

 independent zymotic process. And during the 

 process thus initiated, a matter (contagium) ap- 

 pears and increases in certain of the fluids or tis- 

 sues of the body, which is capable of spreading 

 a similar disease far and wide among receptive 

 members of the community. 



Can the germless liquor potassae plus the favor- 

 ing conditions (the principal of which is a certain 

 high temperature) be regarded as the "cause" 

 of the fermentation ? The answer does not ad- 

 mit of doubt : the effect in question would not 

 have taken place without their influence. The 

 old logical formula in regard to the word, ccssante 

 causa, cessat effectus, completely justifies this point 

 of view ; and so also does the definition of Sir John 

 Herschel. A " cause," said this philosopher, is 



have already directed your attention to the analogy 

 between the action of an organized ferment and a con- 

 tagious fever. The analogy is probably real, in so far, 

 at least, that it leads us to the inference lhat contagi- 

 um, like a ferment, is something that ia alive. ... If, 

 then, the doctrine of a contagium vivum be true, we 

 are almost forced to the conclusion that contagium 

 consists (at least in the immense majority of cases) 

 of an independent organism or parasite ; and it is in 

 this sense alone that I shall consider the doctrine, . . . 

 it is more than probable, looking to the general analogy 

 between them, that all infective diseases conform in 

 some fashion to one fundamental type. If septic Bac- 

 teria are the cause of septicemia, if the Spirilla are 

 the cause of relapsing fever, if the Bacillus anthracis 

 is the cause of splenic fever, the inference is almost 

 irresistible that other analogous organisms are the 

 cause of other infective inflammations and of other 

 specific fevers."— September, 1877. 



" an assemblage of phenomena which occurring, 

 some other phenomenon invariably commences or 

 has its origin." 



But there is a point of view which must not 

 be lost sight of. It is of considerable importance, 

 and has of late been dwelt upon by G. H. Lewes 

 with his usual force and clearness. He says : '• 

 " The fact that it is a convenience to select some 

 one element out of the group, either for its con- 

 spicuousness, its novelty, or its interest, and that 

 we call it the cause of the change, throwing all 

 the other elements into the background of con- 

 ditions, must not make us overlook the fact that 

 this cause — this selected condition — is only effec- 

 tive in coalescence with the others. Every con- 

 dition is causal ; the effect is but the sum of the 

 conditions." 



This brings us to the only point of doubt which 

 can possibly exist in regard to the interpretation 

 of my experiment. It is whether our most prom- 

 inent causal element, the liquor potassae, exercises 

 its influence (a) partly upon the fluid and partly 

 upon certain otherwise dead or impotent germs 

 still lurking within the vessel, or (b) simply upon 

 the mere chemical constituents of the fluid me- 

 dium, but in such a way as actually to engender 

 minute particles of living matter which thereafter 

 appear as ferment-organisms. 



If a practically dead germ can by any treat" 

 ment be revived, it may take its place as one of 

 the causal conditions leading to fermentation ; 

 hence it is that a certain reserve may still be 

 maintained as regards the absolute proof of the 

 possibility of a germless origin of common fer- 

 mentations, and the almost simultaneous occur- 

 rence of a new birth of living units (archebiosis). 



But all similar grounds for reserve are ab- 

 sent — are non-existent, in fact — in regard to the 

 bearing of this experiment upon the possibility 

 of an occasional independent origin for zymotic 

 disease, whether or not such disease is character- 

 ized by the appearance within the body of any 

 distinctive living organisms. 2 



This I will now endeavor to demonstrate. 



It is the process of fermentation which is 

 supposed to be in part analogous to the zymotic 

 disease. It is true that a contagious something 

 becomes engendered during fermentation and 

 during zymosis, by means of which the process 

 or the disease may be spread abroad. But there 



» "Problems of Life and Mind," vol. ii., p. 390. 



3 The rule is, that organisms are present in fermen- 

 tations, while they are, so far as we know, quite ex- 

 ceptional in zymotic diseases. 



