108 PRESIDENT’S ADDRESS—SECTION D. 
Such reference to protoplasm was, however, no explanation, though 
it was the first step towards an understanding of the problems of 
living matter. For many years Max Schultze’s definition of 
protoplasm was generally accepted. He regarded the protoplasm, 
or cell-substance, as a homogeneous, glassy, and transparent sub- 
stance, viscid, or of firmer consistence. The cell-substance 
contained a nearly homogeneous nucleus of rounded form, which, 
in turn, contained the nucleoli. The cell-substance was regarded 
as separable only into the homogeneous groundmass or protoplasm 
and the numerous imbedded granules. 
Further research, however, aided partly by later improvements 
in the microscope, has shown that the protoplasm is far from 
being homogeneous; that it usually, if not always, possesses a 
definite and complicated structure, being composed of two different 
substances, not granules and «a homogeneous groundmass, but 
threads or a network of fibres and intermediate substance. The 
extraordinary changes which the network in the nucleus of the 
cell undergoes during the process of multiplication have formed 
the subject of a vast number of papers during the last decade. It 
seems improbable that with this microscopic analysis we have 
arrived at all the intricacies of the structure of living matter. 
The advance of physiological study has shown the intimate 
correspondence of structure with function, it has shown that 
with every variation in the structure of an organ there is asso- 
ciated a variation in the function or duty of that organ. Physio- 
logical analysis has indeed gone further, and in many cases has 
demonstrated a complexity of function which is greater than that 
of visible structure. This structure of living matter is of no 
ordinary interest to the biologist. We have in the microscopic 
speck of protoplasm all the fundamental properties of the living 
organism presented to us. Such a speck of protoplasm may 
contain within itself all the potentialities of development of the 
highest or lowest organism. It may develop in one direction into 
a man, or in another into a worm, and we must assume that the 
potentialities of development in the different cases are represented 
materially by the structure and chemical composition of the 
network and intermediate substance. 
It is obvious enough that we are still but at the beginning of 
our knowledge of life. There is a boundless field for generations 
of workers, and we may look forward with confidence to many a 
discovery to delight the human mind and to add to human health 
and happiness, as well as to more material welfare. It is not 
possible for all to be workers in the domain of the biological 
sciences, but all alike will, as living beings, share in the benefits 
of discoveries in the laws governing the world of life. It is on 
these grounds that we can, as students of biology, nost surely 
claim the sympathy of the general public, and will it not be well 
for us to value and foster all friendliness towards our pursuits 
which we receive from their hands ? 
