October 6. 1911] 



SCIENCE 



423 



law. Just as the embryologist used to ex- 

 plain everything by heredity, so the mor- 

 phologist is still inclined to say, ' ' the thing 

 is alive, its form is an attribute of itself, 

 and the phj^sical 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 insig- 

 nificant extent blend with the intrinsic or- 

 ganic forces in producing the resultant 

 form. Herein lies our question in a nut- 

 shell. Has the morphologist yet suffi- 

 ciently studied the forms, external and in- 

 ternal, 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 

 interpreted and described? Has the biol- 

 ogist, in short, fully recognized that there 

 is a borderland not only between physiol- 

 ogy 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, 

 Ehumbler and Dreyer, Biitschli and Ver- 

 worn, 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 of form that 

 are apparent in its movements and in its 

 growth, may in all cases alike be described 

 as due to the action of force. In short, the 

 form of an object is a "diagram of forces" 

 — in this sense at least, that from it we can 

 judge of or deduce the forces that are act- 

 ing or have acted upon it ; in this strict and 

 particular sense, it is a diagram: in the 

 ease of a solid, of the forces that have been 



impressed upon it when its conformation 

 was produced, together with those that en- 

 able it to retain its conformation; in the 

 case of a liquid (or of a gas) , of the forces 

 that are for the moment acting on it to 

 restrain or balance its own inherent mo- 

 bility. In an organism, great or small, it 

 is not merely the nature of the motions of 

 the living substance that we must interpret 

 in terms of force (according to kinetics), 

 but also the conformation of the organism 

 itself, whose permanence or equilibrium i& 

 explained by the interaction or balance o£ 

 forces, as described in statics. 



If we look at the living cell of an Amcebos. 

 or a Spirogyra, we see a something which 

 exhibits certain active movements, and a 

 certain fluctuating, or more or less lasting, 

 form ; and its form at a given moment, just 

 like its motions, is to be investigated by the 

 help of physical methods, and explained 

 by the invocation of the mathematical con- 

 ception of force. 



Now the state, including the shape or 

 form, of a portion of matter is the resultant 

 of a number of forces, which represent or 

 symbolize the manifestations of various 

 kinds of energy; and it is obvious, accord- 

 ingly, that a great part of physical science 

 must be understood or taken for granted as 

 the necessary preliminary to the discus- 

 sion on which we are engaged. 



I am not going to attempt to deal with, 

 or even to enumerate, all the physical 

 forces or the properties of matter with 

 which the pursuit of this subject would 

 oblige us to deal — with gravity, pressure^ 

 cohesion, friction, viscosity, elasticity, dif-> 

 fusion and all the rest of the physical fac-^ 

 tors that have a bearing on our problem. 

 I propose only to take one or two illustra- 

 tions from the subject of surface-tensiouy 

 which subject has already so largely en-, 

 gaged the attention of the physiologists.. 

 Nor will I even attempt to sketch the gen-. 



