CHAPTER 11] 
THE ELEMENTS OF STRUCTURE 
(MorpHotocy) 
ANIMALS may be studied alive or dead, in regard to their 
activities or in regard to their parts. We may ask how they 
live, or what they are made of; we may investigate their 
functions or their structure. The study of life, activity, 
function, is physiology; the study of parts, architecture, 
structure, is morphology. 
The first task of the morphologist is to describe structure 
(descriptive anatomy); the second is to compare the parts 
of one animal with those of another (comparative anatomy) ; 
the third is to try to state the “principles of morphology,” 
or the laws of vital. architecture. 
But just as the physiologist investigates life or activity at 
different levels, passing from his study of the animal as a 
unity with certain habits, to consider it as an engine of 
organs, a web of tissues, a city of cells, and a whirlpool of 
living matter; so the morphologist has to investigate the 
form of the whole animal, then in succession its organs, 
their component tissues, their component cells, and finally, 
the structure of protoplasm itself. The tasks of morphology 
and of physiology are parallel. 
Morphology thus includes not only the description of ex- 
ternal form, not only the anatomy of organs, but also that 
minute anatomy of tissues and cells and protoplasm which 
we call histology. Moreover, there is no real difference 
between studying fossil animals which died and were buried 
countless years ago, and dissecting a modern frog. The 
‘anatomical paleontologist is also a student of morphology. 
