VII 



ANIMAL EXPERIMENTATION AND PRACTICE OF 

 MEDICINE AND HYGIENE 



What knowledge has been added to the 

 practice of medicine and hygiene by these 

 methods? As we look over the list of diseases 

 with which man is afflicted, and think of the 

 studies which have contributed to their elucida- 

 tion, it is difficult to find one, the understand- 

 ing of which has not been helped by animal 

 experiments. 



The study of the infectious diseases is one Infectious 

 of the most brilliant chapters in modern sci- diseases, 

 ence. These diseases in man are found to be 

 due to two classes of parasitic organisms, the 

 bacteria and the protozoa. The bacteria are 

 vegetable; the protozoa are animal. These 

 microscopic organisms are capable of extraor- 

 dinary proliferation, multiplying in a manner 

 almost exceeding the power of calculation. 

 They grow in the warmth of the body and take 

 their nourishment from the substance of the 

 body. Those organisms which produce dis- 



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