38 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
being augmented by additions from the laboratories below, and that is 
constantly being altered by the substitution of new items of improved 
design for those fabricated in the past. It is a temptation to linger here, 
for there are so many things reminiscent of phenomena in plant physiology. 
On this floor abstract reasoning is the principal activity. Details of the 
results achieved below-stairs are sorted, criticized, and classified. Those 
that are unessential are filed, and the others are built into more and more 
elaborate models as the skill on the part of the laboratory operatives in- 
creases and new and better machinery and tools are acquired. 
But it is to the third story that the guide conducts us today. Here 
are quiet rooms, thick with silence, in which the faiths of a science are kept. 
These are stored as sketches prepared in the idle moments of genius : skeleton 
diagrams of the possible relations between many apparently dissimilar 
categories of data. Some of these diagrams may now be viewed as models 
on the second floor. Others have been shown to have inherent fallacies, 
while others are so grand in conception that an infinity of time will be re- 
quired to set in final place all the details of which they hint. 
The largest of these is labeled "Conceptions of the material system," 
So large is it that one is likely to miss the whole in contemplation of its 
parts, for the sketch is a patchwork of many, and the light shed by published 
comments is flickering, so that now one, now another part is illuminated. 
It is now purposed to render one aspect of the material system, thus 
pictured, into concise wording and to contemplate its application to the 
study of the living plant. 
Broadly speaking, the large, composite sketch says: ''A system as a 
whole possesses interrelated properties that may be quantitatively investi- 
gated as such without regarding the molecular constitution of the system 
or the molecular kinetics of its processes, and a quantitative statement of 
the laws of a system as a rule is a helpful antecedent to all theories of the 
cause of its unique behavior." Now the recognition of the living plant 
as such a system is generally being only unconsciously made in plant 
physiology. In physical chemistry a system is sometimes defined as an 
aggregation of matter in, or tending towards, equilibrium. This definition 
is incomplete, for it makes no mention of the fact that systems possess 
peculiar properties that characterize the system as a whole, distinguish it 
from other systems, and can not be obtained by adding together the prop- 
erties of its components. In general every system has certain properties 
characteristic only of itself and not deducible from the properties of its 
parts. This is true of all systems: chemical, mechanical, vital. 
Let us now return to the first floor and note what Physics does. She 
takes systems as she finds them in nature and tries to discover a measurable 
feature that will serve to identify a class of systems, adjudged a class from 
their common behavior in some respect. She further seeks to find a number 
that will, by its magnitude only, indicate the degree to which an individual 
