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29 rest, in which the cilia stood straight like the hairs of a brush. The hot iron being removed the instant that this effect was observed, slight indefinite movement soon began to show itself in individual cilia; and before long all were again in action as before the heat was applied. If the cautery was made somewhat hotter the motionless condition was produced almost immediately, preceded by a momentary period of excessively active motion. But if the warm application was immediately suspended, recovery occurred, as in the former case. And the same experiment might be repeated again and again on the same cells with the same results. But if the warmth was allowed to act for a slightly longer time, or the cautery was made still hotter, recovery never took place, and the bodies of the cells swelled up through endosmotic imbibition of water, having lost all life and obeying the ordinary laws of chemistry.

This simple experiment was in various ways instructive. It indicated that ciliated epithelium cells, like the pigment cells, when acted on by a destructive agency to a degree just short of that which is lethal, are thrown into a state in which their vital functions are suspended but not irretrievably lost. It also showed that the cells which compose the animal organism are individually capable of recovering from this state of suspended vital energy, without any aid from the general circulation or the nervous system.

It further illustrated the important fact that a