1 6S foiirnal of Comparative Neurology and Psychology. 



any known physical or chemical laws. To ask whether, when 

 we have arrived at a complete knowledge of the organic world, 

 the biological phenomena will be found to be explicable in 

 terms of the laws of the inanimate world, is to miss the true 

 significance of the problem. The truth is that both vitalism 

 and the mechanical theory arc undergoing transformation. 

 Each is being interpreted in terms of the other. The reason 

 that the mechanical theory today is inadequate to explain all 

 the biological facts is that this theory was formulated upon the 

 basis of too narrow a range of phenomena. If it is to remain 

 the working hypothesis of the physiologist it must be allowed 

 that development which, as itself an organic phenomenon, 

 every working hypothesis exhibits. To take the mechanical 

 theory as a rigid concept, as it was fixed by thought half a cen- 

 tury ago, is logically as vicious as to push recklessly forward 

 to an unwarranted vitalism. In so far as the neo-vitalism is a 

 protest against the static character of this mechanical theory, it 

 may well be that the truth lies, for the time being, in this swing 

 of the pendulum towards vitalism. It behooves the defenders 

 of the mechanical theory to look to the vitality of the mechan- 

 ical theory itself. 



There are no neurological researches which American stu- 

 dents can claim as their own with greater propriety than those 

 centering about the functional analysis of the peripheral 

 nervous system. The recent phase of this movement may 

 be said to date from the suggestion of Osborn in 1888 of 

 the possibility of an anatomical correlation of certain components 

 of the peripheral nerves and their end organs with corresponding 

 centers within the brain, a correlation of which we had at that 

 time only vague hints. This suggestion was taken up and first 

 worked out in a concrete case for the cranial nerves by 

 Strong in 1895, and since that date has dominated most of the 

 really valuable morphological work on the peripheral nerves ; 

 in fact it is safe to say that no investigators in this field who 

 have neglected to take account of this point of view have been 



