CLASSIFICATION OF SCIENCES 117 



that subject-matter. Two sciences may work 

 and often do work at the same material, but with 

 different ends in view, with different fundamental 

 concepts, and with methods different in detail. 



Let us illustrate. An anthropologist may work 

 for years at a particular societary form, and 

 yet his results may be contributions to biology 

 rather than to sociology. A psychologist may 

 devote himself to the study of cats and dogs, and 

 yet his results may not be contributions to biology 

 in the stricter sense. A physicist may give per- 

 sistent and profitable attention to the electrical 

 changes associated with contracting muscle, and 

 yet though he is in a sense dealing with organisms 

 all the time, his results may be contributions to 

 physics rather than to biology. Similarly, the 

 chemist, for purposes of his own, may give his 

 life to the study of the odoriferous substances in 

 flowers, and yet never ask one biological question. 



THE CORRELATION OF THE SCIENCES. From 

 the classification of the sciences and sub-sciences 

 we turn with a feeling of relief to the idea of 

 their Unity. Blocked apart for practical con- 

 venience, treated of in separate books, expounded 

 by different teachers, investigated in different 

 laboratories, the sciences are, after all, parts of 

 one discipline, illustrations of one method, at- 

 tempts to make clear if never to solve the one 

 great problem of the Order of Nature. They 



