C. W. SOAL 
162 
The physiological theory that the specific properties of the 
organism are a chemical function of its germ-plasm is, moreover, not 
really an induction from biological facts. What we actually observe 
in development, heredity, and variation is that certain material 
complexes—organs, tissues, cells, chromosomes, etc .—change in 
different ways, often periodic and variously correlated in constant 
fashion. Empirical biology is the study of these changes. The actual 
matter of the germ-plasm obviously does not persist during somatic 
life, since all, or practically all, the somatic protoplasm is derived 
ultimately from the primary environment in the course of develop¬ 
ment. The only constant factors are the co-ordinated groups of 
changes that we term cell-division, and cell-development, which give 
rise to definite recognisable types of cell structure, whether in the 
form of chemical compounds or larger material aggregates. The 
germ-cell is simply an observed link in a particular periodic series of 
biological events in some way causally related, and we must ascribe 
its specific properties primarily to this fact. 
It is contended here that the physico-chemical standpoint, 
whether ultimately justifiable or not, is at present of no value as a 
working theory, since the phenomena with which empirical biology 
deals are not obviously physico-chemical in character. It is a facile 
generalisation that may indeed often act as an incubus rather than 
an asset in biological investigations, as will be subsequently shown, 
by leading to an uncritical confusion of different classes of phenomena 
that are qualitatively distinct. It is suggested therefore, that it is 
desirable in the present state of knowledge to devise a working 
theory of development, heredity, and variation framed in other 
than physico-chemical terms. 
From this point of view we shall find it more consistent to discard 
altogether the dualistic conception of organism and environment, at 
least in the sense of implying spatial definition. Biological phenomena 
are regarded simply as changes in the material environment of a 
particular quality, that are variously correlated in groups and se¬ 
quences. We must at present simply accept these correlations as 
observed facts; they form the inductive basis of our science. Any 
sequence of environmental changes that is sufficiently constant and 
distinct may be referred to an organic activity —without prejudice as 
to its ultimate nature. It is simply some particular constant aspect 
of the organism’s behaviour in the course of development, the 
organism itself thus becoming a co-ordinated system of activities. 
An activity is always associated with a series of energy-reactions , but 
