R. A. HARPER 
and remain content with such empty formulae. It is a famihar fact to 
critics of Hterature and art as well as to scientists that every great advance 
in knowledge with new concrete discoveries and every great creative age is 
followed by a period when the new data, instead of being made the basis 
for further advances, become the shibboleths of new schools. Concepts 
that have been fruitful and actually represent a great advance in knowledge 
come to be used in a mystical, absolute, and all-embracing sense quite 
unimplied in their original usage. 
We may return from this brief disquisition on definitions and terminology 
to our theme with an illustration of this misuse of , terms. The term pro- 
toplasm as used by Purkinje was merely descriptive and concrete in its 
reference to the material of young embryos. Von Mohl made it more defi- 
nite and still more specific as the term applied to the slimy viscid material 
which makes up the content of the cell inside the cell wall, which latter 
structure to him was still a very important if not essential element in his 
conception of the cell. He was also still far from free of mystical concep- 
tions as to the nature of life and life-processes as something quite outside 
of and beyond the properties of protoplasm. Huxley made protoplasm 
the physical basis of life, a conception which still allowed for much play of 
the imagination as to the existence of forces and principles which could be 
imagined, as Bergson imagined them, to use the protoplasm as the mere 
physical substratum for the manifestation of their autonomous activities. 
In the elimination from modern biology of mystical conceptions as to vital 
force or forces in a super-physical realm we have come, however, to transfer 
a certain element of mysticism to the conception protoplasm itself, and to 
refer to the properties of protoplasm in quite the same fashion as the mediae- 
valists did to vital force, formative principles, etc. We say or obviously 
imply too easily, especially to our elementary students, that all the func- 
tions of life in plants and animals are explainable as due to the properties of 
protoplasm to assimilate, grow, divide, etc. Such statements are true 
so far as we know, but they are so general, so empty of all concrete specifi- 
cation as to the facts of assimilation, growth, and reproduction, that they 
are mere formalisms quite as deadening in the end to the real progress of 
research and discovery as were the conceptions of the "vital spirits" of 
mediaeval physiology in their relations to the functions of nerves, muscles, 
etc., or the nutrient, reproductive, sentient, etc. soul powers of Aristotle — 
conceptions which when accepted as finalities tended to discourage rather 
than to stimulate research. In stating, then, that I shall use the term 
protoplasm as referring broadly to the whole sum of materials which make 
up the cell, including the cell wall, metaplasm, starch, fat, cell sap, even 
inorganic crystals and water of inclusion, nothing is farther from my inten- 
tion than to give a definition of protoplasm. Protoplasm is in most intimate 
relations of interchange with its environment, and, further, there is surely 
no hard and fast line between its external environment and its so-called 
