COMPARATIVE PHYSIOLOGY 



CHAPTER I 



MUSCULAR CONTRACTION 



Physiological science is concerned with describing those 

 properties which distinguish Hving beings from inorganic 

 objects, and relating the processes specially characteristic of 

 the former to the more familiar and accessible phenomena of 

 which we have exact knowledge in the realm of inanimate 

 matter. It is not legitimate to be dogmatic regarding the 

 extent to which similar principles will be found to hold good 

 both in biological and physical science. But the onus of proof 

 lies on those who discourage the attempt to further this end. 

 There have always been those who wish to set limits upon the 

 extent to which the mechanistic approach to vital phenomena 

 can continue to yield profitable results. On the very eve of 

 Wohler's synthesis of urea, Henry wrote with reference to the 

 artificial production of organic compounds, " It is not probable 

 that we shall ever attain the power of imitating nature in these 

 operations. For in the functions of a living plant a directing 

 principle appears to be concerned, pecuHar to animated bodies, 

 and superior to and differing from the cause which has been 

 termed chemical affinity." It may be said, however, that the 

 validity of a mechanistic outlook stands quite apart from the 

 possibility of manufacturing animate systems, just as truly as 

 the justifiability of interpreting the movements of the heavenly 

 bodies in terms of the dynamical relations of immediate ex- 

 perience is independent of the likelihood that we shall ever 

 succeed in bringing into existence a new satellite for Jupiter. 



B 



