THE CONQUEST OF DISEASE 



tuberculosis, typhoid fever, gonorrhea, pneu- 

 monia, diphtheria, septicemia, puerperal fever 

 (child bed fever), cerebro-spinal meningitis, 

 erysipelas, dysentery, cholera, bubonic plague, 

 leprosy, anthrax, tetanus, and glanders. The 

 principal infective diseases of man caused by 

 known protozoa are: malaria, relapsing fever, 

 syphilis, amebic dysentery, and sleeping sick- 

 ness. 



The scope of this book will not permit a full 

 discussion of all of the diseases with which man 

 is afflicted: some of the more important will 

 be discussed. 



Typhoid Let us, for example, take typhoid fever, a 



fever. disease peculiar to man and not found natu- 



rally among the lower animals. W'hat could 

 they contribute to its study ? In the first place 

 we were never in a position scientifically to 

 combat typhoid until its cause was discovered. 

 This was accomplished by Eberth who isolated 

 the typhoid bacillus and cultivated it artificially 

 in a nutrient medium made of beef and gelatin. 

 This is the first stage of the use of the animal 

 in studying this disease. The study was made 

 possible by sacrificing the cow. Pure cultures 

 of typhoid bacilli are to be found growing in 

 all bacteriological laboratories. In the second 



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