THE CONQUEST OF DISEASE 



and a comparatively small amount of experi- 

 mentation, involves operations upon animals. 

 Operations. These operations are practically all performed 

 with the animal under the influence of an an- 

 esthetic. The natural humanity of the opera- 

 tor not only prompts this but the success of the 

 operation demands it. Scientific work might 

 as well not be done at all as not to be done 

 carefully. Comparatively little of this branch 

 of experimental work is being carried on. A 

 few surgeons are engaged in formal experi- 

 mental operations upon animals. These are 

 surgeons who are perfecting operative proce- 

 dures on animals under anesthesia, for the re- 

 lief of human ills, and who freely publish for 

 the benefit of the whole profession the results 

 of their work. 



In physi- The technic of experiments upon animals 



ology. varies with the nature of the experiment. In 



physiology, if the object is to discover the func- 

 tions of an organ, this is done by exposing the 

 organ, let us say, for example, a glandular 

 structure such as the thyroid or spleen. Then 

 the condition of the gland is observed under 

 various circumstances, as, after feeding, during 

 digestion, or at rest. Its secretion is secured 

 and examined chemically. The blood in the 



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