422 



SCIENCE 



[N. S. Vol. XXXIV. No. 875 



method of experiment, the discovery, for 

 instance, of the wonderful effects of chem- 

 ical or even mechanical stimulation in 

 starting the development of the egg, and 

 again the ceaseless' search into the minute 

 structure, or so-called mechanism, of the 

 cell, these, I think, have rather tended to 

 sway a certain number of zoologists in the 

 direction of the mechanical hypothesis. 



But on the whole, I think it is very mani- 

 fest that there is abroad on all sides a 

 greater spirit of hesitation and caution 

 than of old, and that the lessons of the 

 philosopher have had their influence on our 

 minds. We realize that the problem of 

 development is far harder than we had be- 

 gun to let ourselves suppose : that the prob- 

 lems of organogeny and phylogeny (as well 

 as those of physiology) are not compara- 

 tively simple and well-nigh solved, but are 

 of the most formidable complexity. And 

 we would, most of us, confess, with the 

 learned author of "The Cell in Develop- 

 ment and Inheritance," "that we are ut- 

 terly ignorant of the manner in which the 

 substance of the germ-cell can so respond 

 to the influence of the environment as to 

 call forth an adaptive variation ; and again, 

 that the gulf between the lowest forms of 

 life and the inorganic world is as wide as, 

 if not wider than, it seemed a couple of 

 generations ago."^ 



While we keep an open mind on this 

 question of vitalism, or while we lean as so 

 many of us now do, or or even cling with a 

 great yearning, to the belief that something 

 other than the physical forces animates and 

 sustains the dust of which we are made, it 

 is rather the business of the philosopher 

 than of the biologist, or of the biologist 

 only when he has served his humble and 

 severe apprenticeship to philosophy, to deal 

 with the ultimate problem. It is the plain 

 bounden duty of the biologist to pursue his 



= Wilson, op. cit., 1906, p. 434. 



course, unprejudiced by vitalistic hypoth- 

 eses, along the road of observation and ex- 

 periment, according to the accepted dis- 

 cipline of the natural and physical sci- 

 ences; indeed, I might perhaps better say 

 the physical sciences alone, for it is already 

 a breach of their discipline to invoke, until 

 we feel we absolutely must, that shadowy 

 force of "heredity," to which, as I have 

 already said, biologists have been accus- 

 tomed to ascribe so much. In other words, 

 it is an elementary scientific duty, it is a 

 rule that Kant himself laid down," that we 

 should explain, just as far as we possibly 

 can, all that is capable of such explanation, 

 in the light of the properties of matter and 

 of the forms of energy with which we are 

 already acquainted. 



It is of the essence of physiological sci- 

 ence to investigate the manifestations of 

 energy in the body, and to refer them, for 

 instance, to the domains of heat, electricity 

 or chemical activity. By this means a vast 

 number of phenomena, of chemical and 

 other actions of the body, have been rele- 

 gated to the domain of physical science and 

 withdrawn from the mystery that still at- 

 tends on life : and by this means, continued 

 for generations, the physiologists, or cer- 

 tain of them, now tell us that we begin 

 again to descry the limitations of physical 

 inquiry, and the region where a very dif- 

 ferent hypothesis insists on thrusting itself 

 in. But the morphologist has not gone 

 nearly so far as the physiologist in the use 

 of physical methods. He sees so great a 

 gulf between the crystal and the cell, that 

 the very fact of the physicist and the math- 

 ematician being able to explain the form of 

 the one, by simple laws of spatial arrange- 

 ment where molecule fits into molecule, 

 seems to deter, rather than to attract, the 

 biologist from attempting to explain or- 

 ganic forms by mathematical or physical 



° In his ' ' Critique of Teleological Judgment. ' ' 



