838 THE LAW OP EVOLUTION. 



terrestrial, it becomes distinct in organic and super-organic 

 existences. From the lowest living forms upwards, the 

 degree of development is marked by the degree in which the 

 several parts constitute a co-operative assemblage. The 

 advance from those creatures which live on in each part 

 when cut to pieces, up to those creatures which cannot lose 

 any considerable part without death, nor any inconsiderable 

 part without great constitutional disturbance, is an advance 

 to creatures which, while more integrated in respect to 

 their solidification, are also more integrated as consisting of 

 organs that live for and by each other. The like contrast 

 between undeveloped and developed societies, need not be 

 shown in detail: the ever-increasing co-ordination of parts, 

 is conspicuous to all. And it must suffice just to indicate 

 that the same thing holds true of social products : as, for in- 

 stance, of Science ; which has become highly integrated not 

 only in the sense that each division is made up of mutually- 

 dependent propositions, but in the sense that the several 

 divisions are mutually dependent cannot carry on their re- 

 spective investigations without aid from one another. 



