CHAPTER I 



The Bacteriophage in Disease 



Choice of Diseases to Study. Bacillary Dysentery. B. coli Infections. 

 Typhoid and Paratyphoid Fevers. Avian Typhosis. Barbone. Bu- 

 bonic Plague. Flacherie. Conclusions. 



CHOICE OF DISEASES TO STUDY 



From the point of view of the study of immunity human infec- 

 tion offers an inconvenience. Man is not available for experi- 

 mentation; observation alone is permitted. On the other hand, 

 the study of a human infection, such as typhoid fever or cholera 

 for example, in a refractory animal — and they are all so — can 

 only lead to illusory results. Study of disease in the animal, on 

 the contrary, permits of confirmatory experimentation upon 

 the susceptible animal itself where error is no longer unavoidable. 

 However, this method of procedure is very complicated; the dis- 

 ease does not come to us, we must go to it. 



The study of typhoid fever and of dysentery allows us to show 

 by observation the role of the bacteriophage in the course of the 

 disease. These same phenomena may be reproduced in the 

 course of infection in animals, and it is possible with the latter 

 to conduct such experiments of verification as will confirm that 

 which simple observation has already shown. 



In order to ascertain the influence of the bacteriophage on the 

 morbid state, a method which consists in investigating at random 

 the activity of the bacteriophage in a specimen of material taken 

 at any time whatsoever will not lead to any result. It is neces- 

 sary to take the patient as quickly as possible after the inception 

 of the disease and to examine the feces each day until recovery 

 is complete. The daily findings are then plotted in a curve which 

 is superimposed on that expressing the general state of the indi- 

 vidual, such as the number of stools in dysentery, or the tem- 

 perature in typhoid. A comparison of these two curves allows 

 one to draw a conclusion. This mode of procedure necessitates 



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