The next ten pages are devoted to organic development from the protozoa, the lowest tiny animal forms, to crustacea--crabs etc.,--which are materially higher in the animal scale. This development is marked by increasing mutual dependence of parts and a growing division of labor. It is compared to the development of society from primitive Bushmen to the early Anglo-Saxons, during which corresponding phenomena are traced. He escapes Haeckel’s blunder at least to the extent of calling the two divisions of labor by their proper names. Among animals it is the “physiological” division of labor; in society, the “economical” division of labor. Whether he would have been able to still perceive that distinction in dealing with those ant and bee communities where Haeckel got lost, there is nothing to show. Spencer’s middle-class predilections come out strongly, and a very pretty physiological justification is provided for that wholly admirable section of the community. The first step in the development of an embryo is its division into two main layers of cells--the mucous layer and the serous layer. The mucous layer, that fine inside skin of the body so to speak, absorbs nutriment. But that nutriment must be transferred to the serous layer which builds up the nerves and muscles. Presently there arises between these two a third--the vascular layer. Out of this third layer the chief blood vessels are developed and these vessels serve to transport the nutriment from the inner or mucous layer, which gathers it, to the outer or serous layer, which uses it for the whole organization’s upbuilding. “Well,” says Spencer, “may we not trace a parallel step in social progress? Between the governing and the governed, there at first exists no intermediate class; and even in some societies that have reached considerable size, there are scarcely any but the nobles and their kindred on the one hand, and their serfs on the other; the social structure being such that transfer of commodities takes place directly from slaves to their masters. But in societies of a higher type, there grows up, between these two primitive 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.” It is a pity to disturb this serene complacency, by pointing out that the real transporters of commodities are not the members of the middle class who, as a rule, do little and live well, but that section of the working class which mans freight trains, drives teams and shoves trucks. As for that “higher” class of cells which receives these commodities and consumes them while usefully engaged in building up the nervous and muscular system; such comparison could only apply to society’s brain workers, and it contains no justification for the useless parasitic type represented by such charming persons as Harry Thaw and Reggie Vanderbilt.