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the permanent structure of the lower animals. Indeed, some of the lower forms of animal life are simply cells. How vast the difference between the organism of man, with all its complexity of structure, and that of the Ameba or Actinophrys, which, being merely a homogeneous mass of organic matter, performs all the functions of its simple life without any special organ whatever! Yet, is man any less a unit than the Ameba, or any other simple organism? Does his multiplicity of organs impair the integrity of his anatomical and physiological oneness? Is the circulation independent of respiration? Is digestion independent of the circulation? Can any one organ act independently of the others? Is not the entire series of parts, organs, and functions bound up in complete and inseparable unity? The vicarious action of one organ for another has been a question among physiologists; and if admitted, as in the case of the salivary glands acting for the kidneys in profuse spitting, and the skin for the liver, the vicarious function can only obtain to a slight degree and in a temporary manner. The destruction of any considerable organ involves the destruction of all the rest. I repeat that the integrity of the physiological unity at the top of the scale, is far more complete, with all its complexity, than is the integrity of the physiological unity at the bottom of the scale, with its marked simplicity of structure. By no sort of legerdemain or surgical skill can we make an individual mammal become two. If we divide it, the whole dies. Not so, however, with some of the lower grades of animal existence. Cut a hydra into thirty or forty pieces, and each piece will become a distinct animal--a facsimile of the original one. In quite an analogous way do a large number of animals at the lower end of the scale propagate, by segmentation and division; one individual becoming two, two four, and so on. Many examples might be adduced to show the absence of organized unity in the lower orders of the animal creation. Thus, in the annelid, which is composed of a great many similar rings, and is regarded as quite a complex creature, there is so little dependence of one part on another, that a number of the rings may be destroyed without any injury to the rest. The Synapta, when in want of food, will amputate its own body to procure the necessary supply; and it has been observed to repeat the operation, until it 'had by degrees eaten away the whole o
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