GREATER PROBLEMS OF BIOLOGY—THOMPSON. 385 
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 variation; and again, that the gulf between 
the lowest forms of life and the inorganic world is as wide, if not wider 
than it seemed a couple of generations ago.! 
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 hypoth- 
eses, 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,' that we should explain, just as far as we possibly 
can, all that is capable of such explanation, in the light of the prop- 
erties 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 mani- 
festations 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withdrawn from the mystery that still attends on life, and by this 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, 
~ 
1 Wilson, op. cit., 1906, p. 434. 2Tn his Critique of Teleological Judgment. 
38734°—sm 1911 25 
