144 On the Campus 



ity is but a tendency, perhaps best described as the con- 

 tribution of past experiences. The tendency of the plant 

 to grow upward is due to special causes. This too is a 

 response to be mentioned later on. The point here is 

 that the tree, for instance, with an imperative call to 

 grow upward, grows straight upward on the same prin- 

 ciple that the farmer-boy makes perpendicular his flag- 

 staff, or the architect raises straight up his most perfect 

 spire. 



I am not now speaking of the fact that plants obey 

 the law of gravity but that they respond to its binding 

 force and yet strangely use it. For instance, while the 

 tree grows erect, roots down and stem up, you cannot 

 make these parts of the tree or plant do anything else, 

 except by obliterating gravity. We have a machine 

 called the klinostat on which germinating seeds are car- 

 ried slowly round and round in a vertical plane. Here, 

 up and down forever change places, and the poor plants 

 are smitten, so to say, with vertigo and roots and stems 

 grow every which way ; but, you take grains of corn and 

 plant them root end up, and the root will go down every 

 time, and the stem will start up; they will pass each 

 other, each turning one hundred and eighty degrees to 

 do it. Take peas or beans that have started to grow and 

 turn them wrong side up, hang them in moist air under 

 a bell-jar, and they will right themselves in a few days, 

 with the certainty of an acrobat. We think it very re- 

 markable that we can tell when things are level ; we are 

 rather proud of the fact that we have the privilege of 

 becoming seasick, and we talk learnedly of semi-circular 

 canals and all that sort of thing, but what shall we say 



