182 BIOLOGY AND ITS MAKERS 
ing to living organisms only. In its most complete form, 
this idea provided for a distinct dualism between living and 
lifeless matter, making all vital actions dependent upon the 
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eta 755 MT 
Fic. 54.—ALBRECHT HALLER, 1708-1777. 
operation of a mystical supernatural agency. This assump- 
tion removed vital phenomena from the domain of clear 
scientific analysis, and fora long time exercised a retarding 
influence upon the progress of physiology. 
