Page:Popular Science Monthly Volume 12.djvu/758

738 the same healthful condition. This one assumes a branched or tree-like form, and is, if possible, more elegant and beautiful than the last. Its zoöthome, when fully expanded, seems to completely hide the whole corallum, and nothing is visible but one mass or tree of living, moving flowers.

This polyp does not elongate itself so much as does Astrangia, and its tentacles are much shorter; and, instead of being white, it is of an umber-like color, and covered all over with iridescent hues. Its septa, or radiated plates of the corallum, are the same as in Astrangia. The common mass of coral is of a more solid, stone-like nature; the epitheca, or outer coral layer, which the Astrangia has not, and the endotheca, or coral inside the cells, are also more compact and hard.



HLOROFORM is a colorless, volatile, oily liquid; it is denser than water, and does not mix with it. It was discovered by Soubeiran in 1831, and Soubeiran's process for obtaining it is still in use, viz., distilling alcohol with calcium hypochlorite and lime. The hypnotic properties of chloroform were discovered in 1847 by Flourens, a few months after Jackson had recognized similar properties in ether; but the first surgeon who made use of it in an operation on the human subject was Simpson, of Edinburgh, in November, 1847. Since then, the use of chloroform has become so general, that nowadays no great operation in surgery is attempted without employing it. We may, therefore, justly regard the discovery of surgical anæsthesia as one of the greatest scientific achievements of the present century, so fruitful of benefits to the human race.

The principal effect of chloroform is the paralysis of sensibility, or anæsthesia. In so far forth it acts upon the mind, for sensibility is only one of the forms of mind; but this point, which as yet is rather obscure, calls for a few words of explanation.

Two great functions devolve upon the nervous system, sensibility and motion: it is through sensibility that we receive impressions from without; and it is through the excitation of the muscles, or movement, that we manifest our will, or act upon external objects. In the absence of both disease and poisoning, the will—that is, the