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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 ad- 

 vancement 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 ex- 

 periments, 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 in- 

 gredients were carbonate of lime in the former, and phosphate of 

 lime in the latter, the bases in both consisting of different modifi- 

 cations 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 Madre- 

 pores and Millepores (like several of the shells) are formed of a gela- 

 tinous 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 mem- 

 brane, so formed as to cover the stem in the manner of a sheath or 

 tube. That the other Gorgonise 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 Gorgoniae, 

 and only differ from these and from each other by the quality of tex- 

 ture. And lastly, that the Alcyonia are likewise composed of a soft 



