ACTION AND STRUCTURE DUE TO POWER. 



351 



cerning the operation of the so-called laws of evolution and 

 natural selection, it is much to be desired that the advo- 

 cates of those doctrines would explain and illustrate by dia- 

 grams the several changes which, according to their view, 

 may be conceived to occur during the gradual elaboration 

 of such organs by gradational improvements as regards the 

 several tissues of which they are composed. Surely it is 

 very remarkable that not one of the many authorities by 

 whom evolution has been accepted and taught has yet 

 attempted to illustrate his view by appealing to the evolu- 

 tion of some very minute organ like that which we have 

 been considering. Here are several distinct tissues near 

 to one another in a very small space the whole most 

 favourable for minute investigation, and for determining the 

 several changes through which the tissues pass during their 

 formation. 



The several actions of the organ are dependent, as has 

 been already shown, upon the arrangement and relations of 

 the different constituent parts to one another, and their con- 

 nections. All this was, however, determined when the 

 bioplasts, out of which the tissues were formed, were made 

 to take their appointed places. But the action of the 

 tissues can continue only as long as they retain their in- 

 tegrity, and this depends upon the vitality of the little 

 bioplasts connected with them. If the latter lose their vital 

 powers, the organ no longer acts. No explanation of the 

 action of the tissues can therefore be adequate which does 

 not also include an explanation of the vital action of the 

 bioplasts themselves, and of the bioplasm from which these 

 emanated. 



The idea that the perfect action of any tissue or organ 



