TYPEOID-FEVER POISON. 519 



typhoid fever and no other disease the world over, and under all con- 

 ditions. The question comes up — and the pjthogenic (putrefaction) 

 theory must be competent to afford an answer, or it will have to be 

 abandoned — In what way can an infection, which must be composed of 

 many heterogeneous and opposing elements, and produced under widely 

 different conditions, be capable of producing in different individuals, 

 each affording a nidus for the development of the poison under an 

 almost infinite diversity of circumstances, one uniform train of symp- 

 toms, one specific, well-marked disease ? The answer to this is, that 

 it depends on the kind of matter decomposed. To human excrement, 

 above all others, has been given this fatal power. To this recently 

 sewer-gas, which we have already excluded from the chain of possible 

 causes, has been added. But typhoid fever has never been produced 

 by experiments with decomposing substances, nor by products of de- 

 composition accidentally introduced into the human body ; and, further, 

 it is opposed to our daily experience. There are vast numbers of houses 

 in which the aflfluvia of vaults may be detected in all the rooms, others 

 in which the inmates are constantly inhaling sewer-gas, and the fixed as 

 well as the transient inhabitants escape the disease. It is safe to say 

 that cities with defective sewerage are the rule ; that some cities and 

 villages are more filthy than others ; that in some quarters of a city the 

 decomposition of organic and excrementitious matter is constantly 

 going on ; and yet we find typhoid fever prevailing independently of all 

 these theoretical sources of infection : we find it localized in one sec- 

 tion, even in one block of buildings, while others presenting equally 

 favorable conditions have not produced "a case within the memory of 

 man. 



The theory has been seriously damaged by its friends. Not only 

 typhoid fever, but a series of specific diseases, of the origin of which we 

 are in a measure ignorant, have been referred to the decomposition of 

 organic substances. Dysentery, yellow fever, cholera, typhus fever, 

 and the plague have been assigned to this cause. Liebermeister says 

 that this " very circumstance shows that to explain the origin of typhoid 

 fever by a general and indefinite assumption of a decomposition of 

 organic substances is not satisfactory. It is not every kind of decom- 

 position that can produce typhoid fever ; it must be some specific form 

 of decomposition which elaborates as a specific product the poison of 

 that disease." 



In the epidemic which we are studying we have excluded the theory 

 of contagiousness. We saw in the conditions reasons for excluding 

 the sewers as a means of extension ; and I trust, from what I have said 

 of the nature of the disease-germs, the reader is willing to admit that 

 I have some reason for the belief that we can not find an origin de novo 

 in the house-vaults. 



The atmosphere in this epidemic is not a probable means of the 

 extension of the germs. We are not able to say positively that the 



