Experiments and observations on shell and bone / [Charles Hatchett].

  • Charles Hatchett
Date:
[1799]
Catalogue details

Licence: Public Domain Mark

Credit: Experiments and observations on shell and bone / [Charles Hatchett]. Source: Wellcome Collection.

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    effervescence was produced, and a thin external stratum was dissolved; after which, it remained in a perfectly coriaceous state, and complete, in respect to the original figure. The dissolved portion, being examined by the usual precipi- tants, proved to be carbonate of lime, without any mixture of phosphate; but, in another species of the Asterias, which had twelve rays, (Asterias papposa,) I discovered a small quan¬ tity of phosphate of lime. I am therefore induced to sus¬ pect, that in the different species of the Asterias, nature makes an imperfect attempt to form shell on some, and a crustaceous coating on others; and that a series of gradations is thus formed, between the testaceous, the crustaceous, and the coriaceous marine animals. It was now requisite to ascertain if phosphate of lime is a component part of the substance which covers the crustaceous marine or aquatic animals, such as the crab, lobster, prawn, and crayfish. Pieces of this substance, taken from various parts of those animals, was, at different times, immersed in acetous, and in diluted nitric acid; those which had been placed in the diluted nitric acid, produced a moderate effervescence, and in a short time were found to be soft and elastic, of a yellowish-white colour, and like a cartilage which retained the original figure. The same effects were produced by acetous acid, but in a less degree; in the latter case also, the colouring matter remained, and was soluble in alcohol. All the solutions, both acetous and nitric, afforded carbonate and phosphate of lime, although the former was in the largest proportion. There is reason to conclude, therefore, that phosphate of lime, mingled with the carbonate, is a chemical characteristic which
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