Darwinism and Experimentation in Botany 123 



Experimentation consists in acts or operations by which 

 organisms are allowed to carry out their functional performances 

 under controlled conditions, average, extreme, normal, and ab- 

 normal, allowing examination at will in order to discover, 

 establish, illustrate or confirm conclusions as to the principles 

 involved, the causal relations presented and the correlations 

 manifested. It is impossible to conceive living matter without 

 its environmental setting and an essential feature of experi- 

 mentation consists in adjustment and measurement of environic 

 factors, to obtain a basis for the estimation of deviations from 

 the customary or normal throughout the entire range of reaction, 

 thus exhausting the possibilities. Observation, on the other 

 hand, consists in the simple scrutiny, however minutely carried 

 out, of things as they appear in a state of nature, and it is evi- 

 dent that the information obtained in this manner is of great 

 importance when it supplements experimental results, but is, in 

 itself, often disastrously misleading. Some aspects of descent 

 and heredity were recognizable in the multifold observations 

 of Darwin, yet it is notable that of the generalizations proposed 

 by him, those most generally accepted and finally founded are 

 the ones subjected to experimental proof by himself, or others. 



The general procedure by which we experiment with func- 

 tional features of organisms, or their ontogenetic or morpho- 

 genetic development is too well known to need explication. 

 It consists essentially in setting the organism in action and 

 calibrating the products, whether these be movements, chemical 

 structures, tissue formations, tropistic reactions, correlations, 

 altered rhythms or reproductive departures. The technique 

 of such work is described in detail in laboratory books on plant 

 physiology, and the limitations of pedagogic work are such that 

 but brief attention may be given to any particular phase of 

 plant activity, consequently it may not be adequately presented. 

 Xow if attention be wholly directed to genetics, especially in 

 botany, it may be seen that not only have we perfected new methods 

 of investigation, but that we have used them to some effect in 

 uncovering principles by which inheritance is governed. Al- 

 lusion to some of the more important features may not be out 

 of place 



