12 MODERN BIOLOGIC THERAPEUSIS 



Biology The advancement of scientific medi- 

 cine in the second half of the nineteenth century 

 was characterized by the introduction of a bio- 

 logic view of morphology and physiology; out 

 of which came the sciences of cellular pathol- 

 ogy, bacteriology and parasitology, which had 

 in them the charm of novel methods of treat- 

 ment by means of sera and vaccines. The im- 

 mense growth of general biology in our time is 

 principally due to the theories of Darwin (1809- 

 82), whose bent toward natural history was set 

 by his boyhood interest in botany and his five 

 years' cruise as naturalist. Darwin's "Origin 

 of Species By Means of Natural Selection" was, 

 perhaps, the most wonderful piece of synthesis 

 in the history of science ; and his extraordinary 

 marshalling of facts, in evidence of the " sur- 

 vival of the fittest" by natural selection in the 

 struggle for existence, had a far-reaching influ- 

 ence upon biologic speculation. It created the 

 science of comparative physiology and pathol- 

 ogy by pointing to the close structural and func- 

 tional relationship between human tissues and 

 those of animals and plants. 



Huxley's text books on physiology (1866) 

 which passed through thirty editions and those 



