September 6, 1907] 



SCIENCE 



313 



strike. I was at a window in the university 

 building, looking westward toward a valley, 

 at the center of which, about a quarter of a 

 mile away, there was a field with a few iso- 

 lated trees. A thunderstorm coming up 

 slowly from the southwest gave me hopes of 

 seeing the lightning strike. I saw it strike 

 one of these trees. The flash appeared to me 

 as a superb column or shaft of light, about 

 four or five hundred feet high, and about 

 eight or twelve inches in diameter, perfectly 

 straight, vertical and steady. The shaft was 

 white, the base, however, was distinctly red, 

 like the fire of a conflagration, and tinged 

 probably with a little orange. This column 

 of light seemed to stand between the two 

 diverging stems of the tree. It lasted for 

 about two seconds. The thunder was loud, 

 but not the loudest I have ever heard. A 

 light rain was falling at the time. 



The effects of the flash seemed to be none 

 whatever. The tree was not shattered and was 

 not set on fire. Some cows grazing about a 

 hundred feet away paid no attention to the 

 discharge, except one which walked toward 

 the tree, as if interested in something there, 

 and then turned around and continued to 

 graze. 



The nest morning I examined the spot 

 closely. The tree was a cottonwood and stood 

 in moist ground. It consisted of two trunks, 

 about eight and twelve inches in diameter, 

 diverging from a common base towards the 

 north and south. The southern or smaller 

 one had the bark stripped off its western side, 

 in the shape of a broad ribbon, about two 

 yards long and six inches wide. The east 

 side showed two furrows starting from above 

 the same branch, about ten feet above the 

 ground, and running downward in irregular 

 paths. These furrows seemed to have been 

 plowed by a piece of steel and the bark torn 

 off by violence, because there was no sign of 

 scorching or any change of natural color. 

 There was absolutely no other noticeable ef- 

 fect. I was told that a horse standing near 

 the tree had been thrown over a fence, badly 

 stunned but not otherwise injured. 



William F. Eigge 

 Creighton University 



SPECIAL ARTICLES 



THE METHOD OF TRIAL AND THE TKOPISM 

 HYPOTHESIS 



In his recent book entitled " Behavior of 

 the Lower Organisms" Professor Jennings 

 has drawn attention to the existence of an 

 issue between two attitudes assumed by in- 

 vestigators in attempts to interpret the be- 

 havior of organisms. His own position' is 

 made sufficiently clear. He is frankly hostile 

 to what he conceives to be the essentials of 

 the tropism hypothesis, and is equally devoted 

 to what he has called the " method of trial " 

 as a means of explaining facts for whose in- 

 terpretation he believes the tropism hypothesis 

 to be entirely inadequate. 



My reason for venturing upon the present 

 discussion of the issue thus emphasized lies 

 in the fact that, while I have been much 

 impressed by the admirable plea which Pro- 

 fessor Jennings has made for the method of 

 trial, I do not quite see the force of his main 

 contentions, as applied either to the destruc- 

 tion of the tropism hypothesis or to the sup- 

 port of its successor. 



The value of any hypothesis may be esti- 

 mated according as it does or does not (1) 

 accord with the facts, (2) simplify the prob- 

 lem to be solved, (3) suggest a new line of 

 advance. These tests may be applied to the 

 hypotheses that at present concern us. The 

 views of Professor Jennings will be consid- 

 ered first. 



Professor Jennings attempts to account for 

 the phenomena of organic behavior on the 

 basis of two principles. According to one, 

 " behavior is based fundamentally on the selec- 

 tion of varied movements." According to the 

 other, " the resolution of one physiological 

 state into another becomes readier and more 

 rapid through repetition." These are the 

 " primary facts for the development of be- 

 havior." Given organisms that react to 

 changes in their environment, given a variety 

 of responses to the same conditions, and the 

 material is provided for the development of all 

 types and grades of organic behavior in ac- 

 cordance with the two principles just stated. 



This is obviously a strict application to the 



