308 WILLIAM MORTON WHEELER 
with the organism as a dynamic agency acting in a very complex 
and unstable environment. In using the term organism, there- 
fore, I shall drop the adjective ‘living,’ since I do not regard pickled 
animals or dried plants as organisms. 
As I wish to describe a peculiar type of organism, I may be 
asked, before proceeding, to state more concisely what I mean by 
an organism. It is obvious that no adequate definition can be 
given, because the organism is neither a thing nor a concept, but 
a continual flux or process, and hence forever changing and never 
completed. As good a formal definition as I can frame is the follow- 
ing: An organism is a complex, definitely codrdinated and there- 
fore individualized system of activities, which are primarily 
directed to obtaining and assimilating substances from an envir- 
onment, to producing other similar systems, known as offspring, 
and to protecting the system itself and usually also its offspring 
from disturbances emanating from the environment. The three 
fundamental activities enumerated in this definition, namely 
nutrition, reproduction and protection seem to have their incep- 
tion in what we know, from exclusively subjective experience, 
as feelings of hunger, affection and fear respectively. 
Biologists long ago constructed an elaborate hierarchy of organ- 
isms. Those of a speculative turn of mind, like Spencer and Weis- 
mann, postulated the existence of very simple organisms, the 
physiological units, or biophores, which, though invisible, were 
nevertheless conceived as combining the fundamental activites 
above enumerated. These biophores were supposed to form. by 
aggregation the cells, which may exist as independent organisms 
in the Protozoa and Protophyta or unite with other cells to form 
more complex aggregates, for which Haeckel’s term ‘persons’ 
may be adopted. The person may be merely a cell-aggregate or 
consist of complexes of such aggregates as the metameres of the 
higher animals, for the separate metameres, according to a very 
generally accepted theory, are supposed to be more or less modi- 
fied or highly specialized persons. Somewhat similar conditions 
are supposed to obtain in the composition of the vascular plants. 
The integration both of the metameric and non-metameric Meta- 
zoa may proceed still further, the simple persons combining to 
