CONTRIBUTIONS TO 

 PLANT PHYSIOLOGY 



THE DEPARTMENT OF PLANT PHYSIOLOGY 



By BURTON E. LIVINGSTON 



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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