584 GENERAL CONSIDERATIONS 



tion which prevents the development of hydrophobia if used promptly- 

 after the bite of a rabid dog. This followed previous similar work on 

 anthrax and chicken cholera. 



635. Recent Advances. — -No attempt will be made to follow the 

 course of recent investigations in any of the fields of zoology, though 



Fig. 399. — Louis Pasteur, 1822-1895. {From Shull, "Principles of Animal Biology," 

 after Garrison, "History of Medicine," and by the courtesy of McGraw-Hill Book Company, 

 Inc.) 



since the beginning of the present century tremendous advances have 

 been made and knowledge is now so extensive and progress so rapid 

 that only the specialist in any field can hope to keep fully abreast with the 

 discoveries in that field. 



