GREATER PROBLEMS OF BIOLOGY—THOMPSON, 881 
the problem of the origin of species, are indeed magnalia nature; 
and I take it that inquiry into these, deep and wide research specially 
directed to the solution of these, is pee aaa of the spirit of our 
time and is the password of the younger generation of biologists. 
Interwoven with this high aim which is manifested in the biological 
work of recent years is another tendency. It is the desire to bring 
to bear upon our science, in greater measure than before, the methods 
and results of the other sciences, both those that in the hierarchy of 
knowledge are set above and below and those that rank alongside 
of our own. 
Before the great problems of which I have spoken the cleft be- 
tween zoology and botany fades away, for the same problems are 
common to the twin sciences. When the zoologist becomes a student 
not of the dead but of the living, of the vital processes of the cell 
rather than of the dry bones of the body, he becomes once more a 
physiologist, and the gulf between these two disciplines disappears. 
When he becomes a physiologist, he becomes, ipso facto, a student of 
chemistry and of physics. Even mathematics has been pressed into 
the service of the biologist, and the calculus of probabilities is not 
the only branch of mathematics to which he may usefully appeal. 
The physiologist has long had as his distinguishing characteristic, 
giving his craft a rank superior to the sister branch of morphology, 
the fact that in his great field of work and in all the routine of his 
experimental research, the methods of the physicist and the chemist, 
the lessons of the anatomist, and the experience of the physician, are 
inextricably blended in one common central field of investigation 
and thought. But itis much more recently that the morphologist and 
embryologist have made use of the method of experiment and of the 
aid of the physical and chemical sciences—even of the teachings of 
philosophy—all in order to probe into properties of the living organism 
that men were wont to take for granted or to regard as beyond their 
reach under a narrower interpretation of the business of the biologist. 
Driesch and Loeb and Roux are three among many men who have 
become eminent in this way in recent years, and their work we may 
take as typical of methods and aims such as those of which I speak. 
Driesch, both by careful experiment and by philosophic insight; 
Loeb, by his conception of the dynamics of the cell and by his mar- 
velous demonstrations of chemical and mechanical fertilization; 
Roux, with his theory of autodetermination and by the labors of the 
school of Entwickelungsmechanik which he has founded, have all in 
various ways, and from more or less different points of view, helped 
to reconstruct and readjust our ideas of the relations of embryological 
processes, and hence of the phenomenon of life itself, on the one 
hand, to physical causes (whether external to or latent in the mecha- 
