98 



The Plant World. 



ized by the establishment of the theory of descent and the full 

 presentation of the inclusive generalizations of Darwin, especially 

 with regard to natural selection, since the period in which this 

 occurred was one in which a rapid and notable change in the 

 prevailing attitude of the human mind toward natural phe- 

 nomena took place. By the most cursory examination of the 

 products of the scientific activities of the nineteenth century, 

 it may be seen that Darwin's great exposition was in itself the 

 foremost movement in such impending change, not only in our 

 attitude toward nature, but also in the means to be employed 

 in scientific inquiry of all kinds. 



The establishment of the experimental, analytical method 

 )f dealing with natural phenomena by measurement, observa- 

 tion, test and trial may be said to have had its beginning with 

 the work of Becher, the chemist, in 1681, from which time this 

 mode of attack has been used almost continuously in chemistry 

 and physics, a procedure which has placed these sciences on a 

 much more exact basis than those included in biology. The 

 demonstration of the circulation of the blood by Harvey about 

 the time of Becher may be taken to represent the first experi- 

 mentation in physiology, and other isolated instances might be 

 cited up to the close of the eighteenth century. This and the 

 opening of the last century witnessed the efforts of Senebier, 

 Ingenhousz, DeSaussure, DeCandolle and Lamarck, but their 

 efforts were sporadic and without direct or important conse- 

 quence. The arrangement and measurement of the action of 

 organisms under controlled conditions in order to ascertain the 

 principles illustrated, or underlying their action, was not recog- 

 nized in their time, as an efficient means of acquiring knowledge, 

 nor indeed w r as experimentation acknowledged as a legitimate 

 means of interpreting biological phenomena, a state of mind 

 A-hich still finds representation among naturalists, who, not 

 having caught the full force of the current of modern thought, 

 now and then warn us that inheritance, and evolutionary ad- 

 vance are not amenable to measurement and physical-proof , and 

 that the results obtained from study of the domesticated animals 

 and of plants under culture as crops, or in gardens and plantations 

 are of no importance, thereby lending a seventeenth century 

 tinge to discussions of the subject, and giving rise to a situation 



