PRESIDENTIAL ADDRESS. 399 



problem of development is far harder than we had begun to let ourselves 

 suppose : that the problems of organogeny and phylogeny (as well as those of 

 physiology) are not comparatively 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 Development and Inheritance,' ' that we are 

 utterly 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 varia- 

 tion ; 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.' 4 



While we keep an open mind on this question of Vitalism, or while we lean 

 as so many of us now do, 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 course, unprejudiced by vitalistic 

 hypotheses, along the road of observation and experiment, according to the 

 accepted discipline of the natural and physical sciences ; 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 accustomed 

 to ascribe so much. In other words, it is an elementary scientific duty : it is a 

 rule that Kant himself laid down, 5 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 science 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 relegated to the domain of 

 physical science and withdrawn from the mystery that still attends on life : 

 and by this means, continued for generations, the physiologists, or certain of 

 them, now tell us that we begin again to descry the limitations of physical 

 inquiry, and the region where a very different 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 mathematician being able 

 to explain the form of the one, by simple laws of spatial arrangement where 

 molecule fits into molecule, seems to deter, rather than to attract, the biologist 

 from attempting to explain organic forms by mathematical or physical law. 

 Just as the embryologist used to explain everything by heredity, so the morpho- 

 logist is still inclined to say — ' the thing is alive, its form is an attribute of 

 itself, and the physical forces do not apply.' If he does not go so far as this, 

 he is still apt to take it for granted that the physical forces can only to a small 

 and even insignificant extent blend with the intrinsic organic forces in producing 

 the resultant form. Herein lies our question in a nutshell. Has the morpho- 

 logist yet sufficiently studied the forms, external and internal, of organisms, 

 in the light of the properties of matter, of the energies that are associated 

 with it, and of the forces by which the actions of these energies may be inter- 

 preted and described ? Has the biologist, in short, fully recognised that there is 

 a borderland not only between physiology and physics, but between morphology 

 and physics, and that the physicist may, and must, be his guide and teacher in 

 many matters regarding organic form ? 



Now this is by no means a new subject, for such men as Berthold and Errera, 

 Rhumbler and Dreyer, Biitschli and Verworn, Driesch and Roux, have already 

 dealt or deal with it. But on the whole it seems to me that the subject has 

 attracted too little attention, and that it is well worth our while to think of it 

 to-day. 



The first point, then, that I wish to make in this connection is, that the Form 

 of any portion of matter, whether it be living or dead, its form and the changes 



1 Wilson, op. tit:, 1906, p. 434. 



3 In his Critique of Teleoloyical Judgment. 



