94 EEPLIES TO CKITICISMS. 



will claim, as part of his science, all investigations touching 

 the refraction of light : be the substance producing this 

 refraction what it may. And the circumstance that the 

 chemist may test the magnetic or diamagnctic property 

 of a body, as a means of ascertaining what it is, or as a 

 means of helping other chemists to determine whether they 

 have got before them the same body, will neither be held 

 by the chemist, nor allowed by the physicist, to imply a 

 transfer of magnetic phenomena from the domain of the 

 one to that of the other. In brief, though the chemist, in 

 his account of an element or a compound, may refer to 

 certain physical traits associated with its molecular consti 

 tution and affinities, he does not by so doing change these 

 into chemical traits. Whatever chemists may put into 

 their books, Chemistry, considered as a science, includes 

 only the phenomena of molecular structures and changes 

 of compositions and decompositions.* I contend, then, 

 that Chemistry does not give an account of anything 

 as a concrete whole, in the same way that Biology gives 

 an account of an organism as a concrete whole. This 

 will become even more manifest on observing the character 

 of the biological account. All the attributes of an organism 

 arc comprehended, from the most general to the most special 

 from its conspicuous structural traits to its hidden and faint 

 ones; from its outer actions that thrust themselves on the 

 attention, to the minutest sub-divisions of its multitudinous 



* Pcrlinps some will say that such incidental phenomena as those of the heat 

 and light evolved during chemical changes, arc to be included among chemical 

 phenomena. I think, however, the physicist will hold that all phenomena of 

 rc-clistributcd molecular motion, no matter how arising, come within the range 

 of Physics. But whatever difficulty there may be in drawing the line between 

 Physics and Chemistry (and, as I have incidentally pointed out in The Principles 

 of Psychology, $ 55, the two are closely linked by the phenomena of allotropy 

 and isomerism), applies equally to the Comtean classification, or to any other. 

 And I may further point out that no obstacle hence arises to the classification I 

 nm defending. Physics and Chemistry being both grouped by me as Abstract- 

 Concrete Sciences, no difficulty in satisfactorily dividing them in the least affects 

 the satisfactoriness of the division of the great group to whicTi they both belong-, 

 from the other two great groups. 



