4 ANIMAL LIFE 
of a very complex chemical and physical constitution. Its 
chemical structure is so complex that no chemist has yet 
been able to analyze it, and as the further the attempts at 
analysis reach the more complex and baffling the substance 
is found to be, it is not improbable that it may never be 
analyzed. It is a compound of numerous substances, some 
of these composing substances being themselves extremely 
complex. The most important thing we know about the 
chemical constitution of protoplasm is that there are al- 
ways present in it certain complex albuminous substances 
which are never found in inorganic bodies. It is on the 
presence of these albuminous substances that the power of 
performing the processes of life depends. Protoplasm is the 
primitive basic life substance, but it is the presence of these 
complex albuminous compounds that makes protoplasm the 
life substance. A student of protoplasm and the funda- 
mental life processes, Dr. Davenport, has said, “Just as 
the geologist is forced by the facts to assume a vast but 
not infinite time for earth building, so the biologist has to 
recognize an almost unlimited complexity in the constitu- 
tion of the protoplasm.” * 
* The physical structure of protoplasm has been much studied, 
but even with the improved microscopes and other instruments neces- 
sary for the study of minute structure, naturalists are still very far 
from understanding the physical constitution of this substance. While 
the appearance of protoplasm under the microscope is pretty generally 
agreed on among naturalists, the interpretation of the kind of structure 
which is indicated by this appearance is not at all well agreed on. 
Protoplasm appears as a mesh work composed of fine granules sus- 
pended in a clearer substance, the spaces of the mesh work being com- 
posed of a third still clearer substance. Some naturalists believe, from 
this appearance, that protoplasm is composed of a clear viscous sub- 
tance, in which are imbedded many fine granules of denser substance, 
and numerous large globules of a clearer, more liquid substance. Other 
naturalists believe that the fine spots which appear to be granules are 
simply cross sections of fine threads of dense protoplasm which lie 
coiled and tangled in the thinner, clearer protoplasm. And, finally, 
