38 ESSENTIALS OF ZOOLOGY 



in applied biology and medicine. In 1861 he put an end to the 

 controversy regarding spontaneous generation of living organisms 

 and established the idea that all life in present times comes from 

 preexisting life. He showed that living organisms cause fermenta- 

 tion and demonstrated that these organisms and others could be 

 killed by heating them to a certain temperature. He showed that 

 materials thus heated and then sealed would not ferment until after 

 they were exposed to the organisms in the air. The pasteurization 

 process grew out of these experiments. He rescued the silk in- 

 dustry of southern Europe by discovering the organism which killed 

 the insects, and he also discovered an immunization process and 

 treatment for hydrophobia. 



The works and lives of such prominent pioneer zoologists of the 

 Southwest as Jacob Boll, Gustaf W. Belfrage, Lincecum, Vliet, 

 Walker, Webb, and others have been described in the recent book 

 by Dr. S. W. Geiser of Southern Methodist University, entitled Nat- 

 uralists of the Frontier. This book is extremely interesting to read. 



References 



Locy, W. A.: Biology and Its Makers, New York, 1915, Henry Holt and Com- 

 pany, Inc. 

 — : The Growth of Biology, New York, 1925, Henry Holt and Company, Inc. 

 Nordenshiod, E.: History of Biology, New York, 1928, Alfred A. Knopf, Inc. 



