40 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
is made to discover the nature of the dynamical systems of which the observed phenomena 
are the motions. The dynamical theories of the different physical sciences are in very 
different stages of development and in almost all of them a sound knowledge of the subject 
is best acquired by adopting, at least at first, the method we have called "elementary," 
that is to sdLy, the study of the connection of the phenomena peculiar to the science without 
reference to any dynamical explanations or hypotheses. 
The italics are mine. 
A glance over some of these secondary sciences (which include such 
theoretically unrelated topics as elasticity of figure in solids, viscosity, cohesion 
of liquids, thermodynamics, geometrical optics, electricity and magnetism) and 
a perusal of a standard text on the subject must be convincing that physics 
does take systems as she finds them in nature and finds mathematical rela- 
tionships between their conveniently measured attributes, without con- 
sidering at the outset any dynamical theory to account for the properties. 
And, lastly, it must be noted that in the mathematical expression, the 
concrete, individual system is represented by one or more constants whose 
magnitudes are determined by independent measurements on the system 
itself. 
It has been objected that plants are far too complicated systems to 
have any such constants, that the variation of one plant from another of 
the sanle species would be so great that there would be no value in the 
constant, that the evaluation of the constant would involve its determina- 
tion for each plant and would require so much work as to defeat the object. 
Perhaps it is useless to discuss the matter in advance, but there are many 
reasons for doubting the cogency of these arguments. Indeed, the more 
one ponders the matter the more one is convinced that estimating the de- 
gree of potential activity of systems by inspections of their surface features 
is a universal method of the human race. In the affairs of life we say that 
one who is successful in the exercise of this method has judgment; symp- 
tomology in medicine is the systematization of the results of such an attitude. 
The botanists of yesterday recorded numberless instances of mor- 
phological characters that are always found associated — or correlated, as 
they said. It is, of course, recognized that structure and function have 
some sort of interrelation, and a good deal of work has been directed toward 
finding the so-called causes of the interrelation." It is becoming likewise 
probable that a great number, at least, of physiological processes are 
correlated. All this would be predictable from the point of view of the 
physical system, predictable, that is, in a rough, general sense; for, of course, 
it has required much scientific imagination to discover these correlations 
and it will involve a great deal of tedious work to evaluate the degree of 
the interrelation. Now, may not the relative magnitudes of morphological 
features be a reflection of, or be quantitatively associated with, the plant's 
ability to carry on its life processes, i.e., the physiological processes that we 
find such difficulty in measuring? If morphological characters have 
