November 3, 1916] 



SCIENCE 



621 



nected more particularly with electrical and 

 electro-chemical phenomena, the periodic 

 law, and radio-activity are awakening us 

 from this dream also. The supposed bed- 

 rock reality of a former generation seems 

 to be melting down before our eyes. The 

 solvent has been the study of particular 

 phenomena, such as those of radio-activity. 

 The professional physicists and chemists 

 have hitherto kept away from the serious 

 study of life. For the most part they have 

 regarded life as something apart: or as a 

 complex physical and chemical phenomenon 

 which is not likely to throw any light on 

 the deeper problems of physics and chem- 

 istry. In this attitude I think that they 

 have been mistaken; but in any case it is 

 evident that we must guard against the 

 quite unwarranted assumption that the 

 only possibility of advance in physiology 

 is by the direct application to life of the 

 physical and chemical ideas which held un- 

 challenged sway for so many years. 



In this reference I should like to reply to 

 some remarks, made partly with reference 

 to my own writings, by my friend Pro- 

 fessor Macallum of Toronto, in a very able 

 and interesting presidential address to the 

 American Society of Biological Chemistry 

 two years ago. 2 After frankly admitting 

 that the apparent difficulties of the mech- 

 anistic interpretation of life "put a task 

 upon the human spirit which is apparently 

 not imposed thereon in the theoretic ex- 

 planation of any other department of sci- 

 ence" he proceeds to argue that this is be- 

 cause "our knowledge of the laws that 

 operate in matter is as yet only a very re- 

 mote approximation to the whole of the 

 lore on this subject that is possibly attain- 

 able and that will be ultimately attained." 

 He feels, however, that this defence of the 

 mechanistic theory is somewhat dangerous, 



2 Journal of Biological Chemistry, XVII., p. 

 VIII., 1914. 



and therefore proceeds to point out "that 

 though we know so little of the properties 

 and laws of matter, we know it with a de- 

 gree of certainty which is not exemplified 

 in the ease of any other department of the 

 known or the knowable, and further that 

 the most rational method of interpreting 

 vital phenomena is to explain the unknown 

 in terms of the known, to trace back the 

 causation of the obscure and mysterious 

 to the operations of wholly natural laws 

 and processes." 



Now with this latter sentiment I am in 

 entire agreement; but I would point out 

 that Professor Macallum had just invoked 

 not what he considers the known, but, on 

 the contrary, the totally unknown prop- 

 erties of matter, to furnish us with a future 

 physico-chemical explanation of life. I 

 confess that there is in his argument a cer- 

 tain theological smack which strongly ap- 

 peals to me as a fellow Scotchman. In the 

 domain of "Apologetics" he would, I feel 

 sure, make a great impression. But in the 

 domain of Natural Science we have to ex- 

 amine arguments somewhat closely, and it 

 seems to me that his admissions, which are 

 right and unavoidable, carry him so far 

 that his defence of the mechanistic theory 

 of life is wholly unconvincing. One can 

 not get round the fact that the mechanistic 

 theory has not been a success in the past, 

 and shows no sign of being a success in the 

 future. 



When we look broadly at biological phe- 

 nomena, it is evident that they are dis- 

 tinguished by one universal characteristic. 

 The structure, activity and life history of 

 an organism tend unmistakably to main- 

 tain a normal. Accident may destroy an 

 organism, or even a whole species, but 

 within limits of external environment 

 which are the wider the more highly devel- 

 oped the organism is, the normal life his- 

 tory of each individual is fulfilled. 



