442 RELATION OF PLANT PHYSIOLOGY TO OTHER SCIENCES. 



Perhaps I shall not be accused of going too far if, finally, I consider 

 a moment the somewhat phautasmically spun threads which bind plant 

 physiology with psychology. I have in mind that work of Fechner, 

 the founder of psychophysics, published in the stormy year of 1848, 

 a book written with the tenderest human sympathy. It had been for- 

 merly thought that plants were incapable of locomotion, and on that 

 basis were distinguished from animals. This view was refuted by the 

 same facts which destroyed the long-held opinion as to the insensi- 

 bility of plants. Now, the last year has brought valuable explanations 

 of the power of sensation in plants, and many fancies of Fechner's as 

 to the sensibility of plants have been transformed into scientifically 

 grounded views. The reception and conduction of stimuli and response 

 to them, as in the nervous system of animals, have been demonstrated, 

 although these organisms have no nerves, but, as Fechner said, func- 

 tion often as if they had nerves. If, now, plants possess a soul in the 

 sense employed by modern psychology, then intimacy with the life of 

 plants would offer the psychologists much support in testing the psy- 

 chical functions from the standpoint of the unity of all organized 

 beings, and the more exact separation of these psychic functions from 

 other life functions. 



1 hasten to the close, and must leave unconsidered many important 

 relations of plant physiology to the other sciences. I have not men- 

 tioned the studies upon the adaptation of flowers to insects, and vice 

 versa, resulting in fruit production in the former — studies which call 

 into existence a new borderland between zoology and plant physiology. 

 I omitted also to mention the physiological elements in plant geography, 

 also the great assistance which mathematics has rendered our science, 

 and must likewise pass over much besides. 



I have been able to trace only in a few characteristic examples the 

 results which issue from a consideration of the relation of plant phys- 

 iology to the other sciences. Essentially my whole treatment of the 

 subject has been merely an example, for whatever holds true in my 

 specialty holds true likewise in every other branch of knowledge, 

 namely, the very intimate union of each with other, often widely sep- 

 arated, branches of learning — a union which, with the progress of 

 research, assumes constantly greater power. 



The relation of the individual branches of science to each other proves 

 to be so complicated, as is clear from the examples cited, that we may 

 well conceive how all attempts must be frustrated which, from Bacon 

 to d'Alembert and from the encyclopedists to the present time, had 

 for their object a classification of the sciences. One can not parcel off 

 the sciences like a building plot. We ourselves have drawn the division 

 lines between the individual sciences, compelled by the limitations of 

 our human mind, which necessitates us to make a division of labor. But 

 with our advances these boundaries disappear ; the individual studies, 

 often inimically opposed, unite into a single whole. Thus science 



