CONTRIBUTIONS TO 
PLANT PHYSIOLOGY 
THE DEPARTMENT OF PLANT PHYSIOLOGY 
By Burton E. Livineston 
The Department of Plant Physiology, established in the 
autumn of 1909, has experienced a very satisfactory growth 
during the seven and one-half years of its existence. It en- 
tered the present Laboratory of Plant Physiology as soon as 
the building was completed, in the winter of 1911-12. The 
laboratory building has been described, with photographs and 
plans, in the Johns Hopkins University Circular for Decem- 
ber, 1916. The present paper is offered as a preface to the 
following preliminary reports of plant physiological work 
now in progress or recently completed, and deals with two 
topics, the general aims of the department and the nature of 
the work so far accomplished or in progress. 
AIMS OF THE DEPARTMENT 
Nature of the Science—Plant physiology occupies a some- 
what uncommon position among the natural sciences, having 
many of the characteristics of a young science, although it 
is not really such. Notwithstanding the fact that people have 
been interested in the physiology of plants for many genera- 
tions, the subject has hardly yet become generally regarded 
as a separate science, and it has usually been included under 
the general designation of botany. Animal physiology, which 
is, of course, the corresponding subdivision of zoology, has 
long been considered as distinct. The simplest way to make 
the content of plant physiology clear to one not acquainted 
with it is to point out that it deals with plants in exactly the 
same way as animal physiology deals with animals. Thus 
it has to do with all the processes that go on in plants, and 
it considers these processes just as physics and chemistry con- 
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