95 



the washing of tlie moliair had been distributed sickened with 

 anthrax and died in numbers. 



The evidence adduced proves that there is at least one 

 infectious disease which owes its origin to the growth and 

 development of micro-organisms within the body of its victim, 

 and to this cause only. And if this be true of one, why may 

 it not be true of others which, like it, are infectious, have their 

 stages of incubation, full development, and of retrogression, 

 show marked febrile symptoms, seldom occur more than once 

 in the same patient, and present in their tissues, in many 

 examples, peculiar forms of micro-organic growths ? AVhv, in 

 fact, may we not infer that every infectious disorder owes its 

 ■origin to its own peculiar organism ? Grant, if you will, that 

 we are in the region of hypothesis ; but in the absence of other 

 satisfactory explanations it is reasonable to adopt the one 

 -which covers a larger number of facts than any other, and 

 which every new discovery tends to confirm. 



The evidence does not rest, however, on the form of disease. 

 There are some diseases of animals in which the facts are 

 almost as well worked out as in anthrax. There is also a fever 

 which attacks man, and known as relapsing fever, in which one 

 of the spiral Bacteria (the Spirochoete Obermeieri) is alwavs 

 found in the blood when the fever is at its height, and disap- 

 pears as the fever declines. Monkeys have been successfully 

 inoculated with this bacterium, and have taken the fever ; 

 .and it is asserted that the same results have followed in the 

 human subject after inoculation with blood taken from a 

 patient while the fever was high, and that no effect was pro- 

 duced with blood taken from the same patient when no fever 

 was present. 



In nearly all the acute infectious diseases Bacteria in some 

 -form are to be found, and cultures can be obtained from them. 

 In measles, diphtheria, erysipelas, smallpox, vaccine lymph, 

 ^nd, as I have lately found, in the hybrid chicken-pox, various 

 forms have been discovered. The history of these is not 

 w^orked out. So also in typhoid fever — with which we are all 

 too familiar — Koch's assistants at the German Board of Health 

 announced last year the discovery of a peculiar organism which 

 they believed to be its cause. During the hist few months I have 

 been making independent researches, and all my investigations 

 point in this direction. And let me note that the clinical history 

 of the disease favours the germ theory of its origin, even 

 t;hough no specific organism can be fixed on as its starting point. 

 TypUoid has been carefully followed up and investigated by 

 Government medical officers in England, and there is a uniform 

 agreement that this fever is a disease associated with the filth 

 of human excreta. There is strong evidence that this excreta. 



