50 BULLETIN OF THE 



once to the consideration of the subject I have selected for the 

 present occasion. 



I propose to invite your attention this evening to some thoughts 

 on the Modern Philosophical Conceptions of Life. The theme is so 

 large that it would be idle to attempt its systematic treatment in the 

 course of a single evening ; nor do I pretend to be in possession of 

 any satisfactory solution of this ancient question, of which I might 

 offer you an abstract or outline, pending the fuller presentation of 

 my results elsewhere. Yet I have ventured to hope that a discus- 

 sion of some of the considerations involved, and a brief statement 

 of certain views that I have been led to entertain, would not be 

 without interest, and perhaps might prove of actual service, especi- 

 ally to those of you who are engaged in biological pursuits. 



Undoubtedly the conception of life most popular at the present 

 time is that which assumes all the phenomena of living beings to 

 be the necessary results of the chemical and physical forces of the 

 universe, and claims, or intimates, that wherever this has not yet 

 been proven to be the case the evidence will hereafter be forth- 

 coming. This doctrine, which may conveniently be designated the 

 chemico-physical hypothesis of life, has readily found its way from 

 the speculative writings of philosophers to the rostrums of some of 

 our teachers of chemistry and physics who boldly declare, in their 

 class-lectures and public addresses, that the forces at work in the 

 inorganic world are fully adequate to explain all the phenomena of 

 living beings, and prophesy that the time is soon coming " when the 

 last vestige of the vital principle as an independent entity shall dis- 

 appear from the terminology of science." * 



Now, most of these gentlemen are not embarrassed by any very 

 definite or detailed knowledge of the physiological and pathological 

 phenomena which a tenable theory of life must be competent to 

 explain, while they do know, or at least ought to know, a great 

 deal of chemistry and physics ; the confidence with which they 

 maintain their creed is therefore readily understood. Much more 

 surprising is it to find the same doctrine embraced by numerous 

 zoologists, physiologists, nay, even pathologists, among them men 

 who cannot for a moment be supposed to be unacquainted with the 

 phenomena to be explained, and of whose abilities and reasoning 

 powers it is impossible for me to think or speak otherwise than re- 

 spectfully. Yet I cannot but believe that they have adopted the 

 chemico-physical hypothesis, not so much because they are really 



