134 The Department of Plant Physiology [332 
sider the processes that go on in inanimate things. Indeed, 
the close relation between the physiology of animals and that 
of plants is becoming so well appreciated in recent years that 
a science of general physiology (dealing with the physics and 
chemistry of all living things) appears to be rapidly devel- 
oping. It is seldom possible to treat any physiological topic 
adequately without reference to both plants and animals. 
Some of the topics:dealt with in plant physiology may be 
mentioned as examples. Such are: water requirement; nu- 
trition by inorganic materials; nutrition by organic ma- 
terials; the exchange of energy between the organism and 
its surroundings; the chlorophyll function; respiration, with 
and without free oxygen; enzymes, activators, hormones, and 
the general phenomena of catalysis; the control of growth 
and development, including reproduction; the physiology of 
movement and its control, and the physics and chemistry of 
protoplasm. 
The non-physiological aspects of biology may be grouped 
together as morphology, which deals with the structures of 
organisms. Perhaps one of the most noticeable aspects of 
physiological endeavor, and one in which it differs remark- 
ably from morphological study at the present time, is this, 
that it has little to do with the general problem of evolu- 
tion and phylogeny. Evolutionary philosophy has been 
built up largely from morphological observations, and it is 
only recently that it has become possible to relate different 
organisms to each other with reference to their physical and 
chemical processes. The evolution of animals and plants has 
never yet been one of the main topics of physiology. 
The sciences of mycology, bacteriology, pathology, ecology, 
etc., all have their morphological and physiological aspects, 
and their subject-matter may be treated from the stand- 
point of static description or from that of process dynamics. 
Thus, that branch of pathology which deals with the identi- 
fication of parasitic organisms is mainly morphological in its 
point of view, while the sciences of toxicology and immunology 
are clearly branches of physiology. It is not without sig- 
nificance that many of the characters by which the bacteria 
