The advantage which Spencer had over Plato and Hobbes is very clearly seen in the first and fourth parallelisms, neither of which could have been made until twenty-one years before, when in 1839, Theodore Schwann developed his great theory that the body is an organized society of interconnected cells. “The importance of this theory,” says Professor Thatcher, “can hardly be estimated. It gave an entirely new view to animal and vegetable life.” At any rate, it served Spencer greatly in this essay.
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.”