THE MECHANISTIC CONCEPTION 39 



classes another the trading or middle class. 

 Equally at first as now, we may see that, speaking 

 generally, this middle class is the analogue of the 

 middle layer in the embryo." The argument seems 

 to me based on very dubious biology, since the bones 

 and muscles, as well as the vascular system, have 

 their origin in the middle layer of the embryo, and 

 though forming a large bulk of the entire body have 

 nothing to do with transportation. The high grade 

 of differentiation of the muscles allies them to the 

 governing rather than to the middle classes, if this 

 analogy must be used here, and the bones hardly 

 fit into the prominent distributive action assigned 

 by Spencer to the mesoblast. Spencer also finds 

 in the red blood cells a resemblance to money in 

 circulation and calls attention to the fact that just 

 as primitive societies have no money, so some lower 

 organisms have no red blood cells. But he quite 

 overlooks the circumstance that in modern communi- 

 ties business is carried on by a credit system with 

 ever lessening requirements as to circulating money, 

 and that for this feature of progress there appears 

 to be no physiological analogue. Again, the com- 

 parison of the governing nervous system to the 

 Houses of Parliament suggested by Spencer seems 

 much too specific a limitation of the social controlling 

 elements. The system seems rather to invite com- 

 parison with the sum of all those groups of individuals 

 in a community that are the means of bringing order 

 and coordination into society whilst influencing its 



