Page:Popular Science Monthly Volume 9.djvu/23

Rh agencies are acting; that the controlling powers, governments, bureaus, judicial officers, police, must fail to keep order when the necessaries of life are not supplied to them by the parts kept in order—we are obliged to say that this mutual dependence of parts is similarly rigorous. Unlike as the two kinds of aggregates are in sundry respects, they are alike in respect of this fundamental character, and the characters implied by it.

How the combined actions of mutually-dependent parts constitute life of the whole, and bow there hence results a parallelism between national life and individual life, we see still more clearly on learning that the life of every visible organism is constituted by the lives of units too minute to be seen by the unaided eye.

An undeniable illustration is furnished us by the strange order Myxomycetes. The spores or germs produced by one of these forms become ciliated monads which, after a time of active locomotion, change into shapes like those of amoebae, move about, take in nutriment, grow, multiply by fission. Then these amœba-form individuals swarm together, begin to coalesce into groups, and these groups to coalesce with one another, making a mass sometimes barely visible, sometimes as big as the hand. This plasmodium, irregular, mostly reticulated, and in substance gelatinous, itself exhibits movements of its parts like those of a gigantic rhizopod, creeping slowly over surfaces of decaying matters and even up the stems of plants. Here, then, union of many minute living individuals to form a relatively vast aggregate in which their individualities are apparently lost, but the life of which results from combination of their lives, is demonstrable.

In other cases, instead of units which, originally discrete, lose their individualities by aggregation, we have units which, arising by multiplication from the same germ, do not part company, but nevertheless display their separate lives very clearly. A growing sponge has its horny fibres clothed with a gelatinous substance, and the microscope shows this to consist of moving monads. We cannot deny life to the sponge as a whole, for it shows us some corporate actions. The outer amoeba-form units partially lose their individualities by fusion into a protective layer or skin; the supporting framework of fibres is produced by the joint agency of the monads, and from their joint agency also result those currents of water which are drawn in through the small orifices and expelled through the larger. But, while there is thus shown a feeble aggregate life, the lives of the myriads of component units are very little subordinated: these units form, as it were, a nation having scarcely any subdivision of functions. Or, in the words of Prof. Huxley, "the sponge represents a kind of subaqueous city, where the people are arranged about the streets and roads in such a manner that each can easily appropriate his food from the water as it passes along."