CHOOSING A RESEARCH PROBLEM 77 



therein lying not in the phenomena themselves but in their rela- 

 tion to other phenomena. While descriptive botany, in all its 

 phases, is and must ever remain the introductory chapter through 

 which the beginner best enters the subject, — just as one enters the 

 field of a great literature by learning mere facts of the meanings of 

 letters and word-signs — yet this is assuredly not now to be con- 

 sidered as an eminently promising line for a productive life-work. 



2. The next step after qualitative description is the relating 

 of the discovered phenomena to one another and to phenomena 

 without the plant. This activity leads at once to the formulat- 

 ing of hypotheses and the institution of experimentation, upon 

 which true physiology now depends for its basis of separate facts. 

 But facts may be related in many ways. If we relate plant hap- 

 penings with reference to time, our activities will be classed as 

 phylogeny and ontogeny. If we relate them with reference to 

 space, we work in anatomy and that part of ecology which deals 

 with geographical distribution. If we relate them to their effects, 

 to the results which they bring about, our work is teleology. 

 Finally, if we relate them to their physical causes, we are studying 

 plant physics and plant chemistry. 



Only the last of the above methods of relating phenomena comes 

 properly within the realm of physiology. Nevertheless, the fun- 

 damental concepts of cause and effect early became in some way 

 confused in the minds of biological students, and the physiological 

 literature abounds in teleological considerations. Thus, as an 

 obvious example, one may read that horizontally placed stems 

 bend towards the source of one-sided illumination in order to bring 

 the leaves into the usual light relation, a quite teleological state- 

 ment. Its etiological counterpart might be, that this bending takes 

 place because of unequal lengthening of tissues upon the shaded 

 and lighted sides of the stem, and results in bringing the leaves into 

 their usual position with reference to light. Failure sharply to 

 distinguish between proximal cause and effect has greatly retarded 

 the advance of our knowledge of plant processes, so much so that 

 the future science of physiology promises to be rather thoroughly 

 reformed; its renascence is already making rapid strides. This 

 consideration cannot be too strongly impressed upon the mind of 



