Chemical Experiments on Zoophytes; with some Observations on the component Parts of Membrane. By Charles Hatchett, Esq. F.R.S. Read June 12, 1800. [Phil. Trans. 1800, p. 327.]
Having completed the series of experiments on the component parts of shell and bone which he described in a former paper, it was suggested to Mr. Hatchett that there still remained a large class of substances belonging to the animal kingdom, namely, the various species of Zoophytes, which had never yet been carefully analysed, and the investigation of which would probably lead to some curious, and perhaps useful inferences. Although aware of the extensiveness of the inquiry, he yet readily engaged in it; and we have now before us the fruit of his indefatigable industry and ardent zeal for the advancement of science.
The first part of the paper contains a full account of the series of experiments he made on the abovementioned substances, Which, in the present pressure for time, we must pass over unnoticed in order to hasten to the second, which consists of observations on those experiments, in the course of which the subject necessarily led to an inquiry into the nature and properties of several other analogous substances, such as horn, nail, hoof, quill, hair, feathers, tortoiseshell, the scales of fish, amphibious animals and insects, albumen, and even muscular fibre.
We must here recollect that in his former paper on shell and bone Mr. Hatchett had arrived at the conclusion that their essential ingredients were carbonate of lime in the former, and phosphate of lime in the latter, the bases in both consisting of different modifications of a glutinous, gelatinous, or membranaceous substance. This conclusion he had the satisfaction of seeing corroborated, and the chain of connexion widely extended, by the facts deduced from the present inquiry. The general results of which are, that the Madrepores and Millepores (like several of the shells) are formed of a gelatinous or membranaceous substance, hardened by carbonate of lime, the difference consisting only in the mode in which these materials are combined: that in the Tubipora, Flustra and Corallina, some phosphate of lime is mixed with the carbonate of lime: that in the Isis the basis is a regularly organized membranaceous, cartilaginous and horny substance, hardened by carbonate of lime. one species only (the Isis ochracea) yielding also a small proportion of phosphate of lime. That the hardening substance of the Gorgonia nobilis is likewise the carbonate of lime, with a small portion of phosphate; but that the matter forming the membranaceous basis consists of two parts, the interior being gelatinous, and the external a complete membrane, so formed as to cover the stem in the manner of a sheath or tube. That the other Gorgonize consist of a horny stem coated by a membrane, which is hardened by carbonate of lime. That the Sponges are of a nature similar to the horny stems of the Gorgonie, and only differ from these and from each other by the quality of texture. And lastly, that the Alcyonia are likewise composed of a soft
