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 hes 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 subject, for such men as Berthold 
and Errera, Rhumbler and Dreyer, Bitschli 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 (cr 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 Ameba 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. 
