CHAPTER V. 



THE EMANCIPATION OF SCIENTIFIC RESEARCH 

 FROM THE YOKE OF PHILOSOPHICAL THEORIES. 



The excessive use of Hypothetical Agents in Physiological 

 Explanations — § I. Vital Phenomena in Fully-constituted 

 Organisms — Provisory Exclusion of the Morphogenic 

 idea — The Realm of the Morphogenic Idea as the 

 Sanctuary of Vital Forced 2. The Physiological Domain 

 properly so called — Harmony and Connection of Pheno- 

 mena — Directive Forces — Claude Bernard's Work — 

 Exclusion of Vital Force, of Final Cause, of the " Caprice " 

 of Living Nature — Determinism — The Comparative 

 Method — Generality of Vital Phenomena — Views of 

 Pasteur. 



The theories whose history we have just sketched 

 in broad outh'ne long dominated science and exer- 

 cised their influence on its progress. 



This domination has ceased to exist. Physiology 

 has emancipated itself from their sway, and this, 

 perhaps, is the most important revolution in the whole 

 history of biology. Animism, vitalism, materialism, 

 have ceased to exercise their tyranny on scientific 

 research. These conceptions have passed from the 

 laboratory to the study; from being physiological, 

 they have become philosophical. 



This result is the work of the physiologists of sixty 

 years ago. It is also the consequence of the general 

 march of science and of the progress of the scientific 

 spirit, which shows a more and more marked tendency 



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