386 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 



the biologist from attempting to explain organic forms by mathe- 

 matical or physical law. Just as the embryologist used to explain 

 everything by heredity, so the morphologist 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 nut- 

 shell. Has the morphologist 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 interpreted and de- 

 scribed ? Has the biologist, in short, fully recognized 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 subje'ct, for such men as Berthold 

 and Errera, Khumbler and Dreyer, Butschli 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 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 acting or have acted upon it; in this strict 

 and particular sense it is a diagram: in the case of a solid of the 

 forces that have been impressed upon it when its conformation 

 was produced, together with those that enable it to retain its con- 

 formation; 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 in- 

 herent mobility. 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 con- 

 formation of the organism itself, whose permanence or equilibrium 

 is explained by the interaction or balance of forces, as described in 

 statics. 



If we look at the living cell of an Amoeba 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 mathe- 

 matical conception of force. 



