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organs ; or at least, we have a much better attitude in the inter- 

 pretation of the facts that have been established regarding these 

 matters. The danger which lies in this attitude is the well known 

 one of teleological reasoning, and consequently it behooves us 

 to have some caution in accepting, without thorough evidence, 

 the interpretations which may be made of the relation of form 

 and function and of special adaptations for special purposes. As 

 some one has written, " so many things may be true and so few 

 things really are in the matter of use of special organs," that we 

 must demand above all things experimental evidence before we 

 can accept as conclusively proved any statement as to function. 

 It is permissible to say without such proof that such and such 

 an explanation is plausible, but beyond that is uncertain ground 

 and mere assertion shows a temerity at once magnificent and 

 pitiable. On the other hand, it is questionable if the extreme 

 attitude of iconoclasm as to long established interpretations is 

 necessarily a wholly reasonable one. Destructive criticism is 

 not difficult, and unless some new and better interpretation is 

 suggested the advance in a scientific sense is not considerable. 



A further development from this physiological attitude is a 

 branch of biological work known as ecology, a study of the 

 relation and adaptation of single plants or whole communities of 

 plants to their environment and to each other. It is the applica- 

 tion in a broad and more philosophical way of the methods of 

 the physiological anatomist coupled with those of the taxonomist ; 

 but, in addition, the work of the botanist touches the field of the 

 physiographer and geologist. Ecology is the endeavor to un- 

 cover the plan of nature as it governs the relations of the differ- 

 ent plant forms in a given area, to understand the why and the 

 wherefore of the association of very different forms in one 

 locality. The keynote of the philosophical development of this 

 topic rests on the conception of the constant struggle of individ- 

 uals or groups of individuals to maintain themselves against other 

 forms, which leads to a balanced relation of the different species 

 in a given flora. Understanding this, we can see why, if this 

 balance is disturbed, the whole fabric of a plant community may 

 be destroyed and a flora swept away. We are also able to 



