126 
science. It has gone a long way toward its 
goal of securing and interpreting data 
bearing on the order of the evolution of the 
various groups of plants and of thus put- 
ting classification on a natural basis. 
Morphology stands to-day with somewhat 
changed ideals as one of the big phases of 
modern botany. Contributing to evolution 
and working along with it, it offers a large 
field for investigation. A little later men 
began to interest themselves especially in 
the functions of plants—how they make 
their food, and from what raw materials it 
comes. This gave rise to Plant physiology, 
the science which lies at the basis of the 
problems of plant production. 
Following this, the destruction of grow- 
ine crops by parasites led to a scientific 
study of the organisms that cause plant dis- 
eases. This interest in the mutual relation 
of host and parasites is the foundation of 
plant pathology, a subject having large 
possibilities in increasing food production 
as well as attractive from the standpoint 
of pure science. 
In 1895 the publication of Warming’s 
book focused interest on a new point of 
view in botany—that of plant societies liv- 
ing together as communities, limited as well 
as favored by a common environment, but 
not grouped at all according to their nat- 
ural relationships in a morphological sense. 
This has given rise to ecology—a somewhat 
unorganized, but hopeful phase of modern 
botany. 
We now have, then, four main lines of 
interest in modern botany—morphology 
and evolution, pathology, physiology and 
ecology. In the broadening of our knowl- 
edge of plants and of our interests in them, 
we have gotten far from the point of view 
of those who looked upon plants as merely 
things to be named—of those whose inter- 
est in plants was merely in the ear marks 
that might be useful for identification. In 
SCIENCE 
[N. S. Vou. XLVIII. No. 1232 
the shifting of interest from this mere nam- 
ing of plants to their natural classification 
as based upon their structure and repro- 
duction, and the broadening of this into 
interest in their functions, their health, 
their diseases, and even their mutual rela- 
tions in plant societies, interest in the plant 
as a living thing has naturally developed. 
In all of the modern phases of botany the 
tendency now is to look upon the plant as 
a living organism with work of its own to 
_ perform its own problems of existence to 
solve. In the very early stages of this in- 
terest it seemed to many persons that the 
mere statement that the plant was a living 
thing was a sufficient explanation of the 
phenomena shown in its activities. Per- 
haps this may still seem so to some. 
The search for a ‘‘vital principle’’? at 
first based on observation and speculation, 
but later professing to find some basis of 
support in the facts of modern experi- 
mental biology has proved unsatisfactory 
as not contributing to progress. Whether 
it is the ‘‘entelechy’’ of Driesch or the ‘‘x- 
entity’’ of Ganong it offers only slight help 
in getting anywhere. Neither the vitalist 
nor the neovitalist offers us a program for 
work. 
During the years immediately preceding 
1900 the tendency to postulate some sort of 
material particle as the ultimate basis of 
life was dominant. These particles or cor- 
puscles were supposed to consist of more 
than one molecule and it was from them 
that the organism was built up in one way 
or another. They were also supposed to be 
the bearers of heredity. 
In botany corpuscular theories resulted 
largely in research, the basic idea of which 
was that the chromosomes produced in the 
nucleus at the time of cell division are the 
bearers of heredity. Since these bodies are 
2Cf. Child, Senescence and Rejuvenescence,’? 
Chap. 1. 
