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the key-note of our thought about them. It is the purpose of 

 experiment to determine how the.se changes are related to changes 

 in the environment, how the organism adapts itself into the 

 circumstances surrounding it. A science which has to do with 

 such phenomena should be vividly alive itself; its methods should 

 be plastic and should not be hampered by custom or habit. 

 The essential point is to get at the truth, and the way to get at 

 the truth is to observe carefully what goes on in nature, realizing 

 all the time that organic nature is nothing but a complex experi- 

 ment, or to observe by means of special experiment, consciously 

 undertaken. ... 



Teachers are very frequently overawed by what they assume 

 to be the difficulty of conducting experiments. They very easily 

 give way to fear that it involves too much apparatus and it is 

 assumed too frequently that experimentation involves large 

 expenditures of money for apparatus. Aside, however, from 

 exceedingly abstruse work, a vast amount of good experimenta- 

 tion can be done with very little apparatus, if indeed we may 

 call it that at all. The simplest means frequently answer the 

 purpose as well as elaborate apparatus. 



The feeling is frequently entertained also that experimentation 

 is too complex for a young student, that it is altogether too dififi- 

 cult and that therefore the work of young pupils must be confined 

 to pure observation. The answer to this is obvious. The real 

 difficulty of science lies not in the method by which knowledge is 

 gained but by the complexity of materials with which it happens 

 to deal. A successful teacher in this regard is one who can skill- 

 fully select the materials and subjects for experimental work. 

 In fact, scientific workers are constantly on the out-look for 

 favorable material, as it is called, that is to say, material which 

 gives the desired result with the greatest ease. For example, 

 we choose the grain of Indian corn for work with pupils because 

 it is large and because the young plant is easily studied for the 

 same reason. We might get the same facts by studying the 

 germination of millet but this would entail the use of a magnifying 

 glass or even a microscope while Indian corn may be studied 

 equally well with the naked eye. If on the other hand, we are 



