12 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



which can hardly be called pleasant. To a great extent 

 the comparatively slow advance of biological sciences is due 

 to this very fact : the unalterable specific nature of biological 

 material. 



But there is still another feature of biology dependent 

 on the same fact. If a science is tied down to specific 

 objects in every path it takes, it first, of course, has to 

 know all about those objects, and that requires nothing 

 else but plain description. We now understand why pure 

 description, in the most simple sense of the word, takes up 

 such an enormous part of every text-book of biological 

 science. It is not only morphology, the science of form, 

 that is most actively concerned with description ; physiology 

 also, in its present state, is pure description of what the 

 functions of the different parts of the body of animals and 

 plants actually are, at least for about nine-tenths of its 

 range. It seems to me important to press this point very 

 emphatically, since we often hear that physiology is from 

 the very beginning a much higher sort of knowledge than 

 morphology, inasmuch as it is rational. That is not at 

 all true of the beginning of physiology : what the functions 

 of the liver or of the root are has simply to be described 

 just as the organisation of the brain or of the leaf, and it 

 makes no difference logically that one species of description 

 has to use the experimental method, while the other has 

 not. The experiment which only discovers what happens 

 here or what happens there, possesses no kind of logical 

 superiority over pure description at all. 



But there will be another occasion in our lectures to 

 deal more fully with the logic of experiment and with the 

 differences of descriptive knowledge and real rational science. 



