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Article A BRIEF SYSTEM OF CONCHOLOGY. Page 1 of 4 →
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A Brief System Of Conchology.
A BRIEF SYSTEM OF CONCHOLOGY .
THE singular regularity , beauty , and delicacy in the structure of the shells of animals , and the variety and brilliancy in the colouring of many of them , at the same time that they strike the attention of the most incurious observers , have at all times excited philosop hers to inquire into and detect , if possible , the causes and manner of their formation . But the attempts of naturalists , ancient and
modern , to discover this process , has constantly proved unsuccessful . M . de Reaumur hitherto appears alone to have given a plausible account , at least , of the formation of the shell of the garden-snail in particular , founded , on a course of very ingenious experiments , related in the Paris Memoirs . He there endeavours to show , that this substance is produced merely by the perspirable matter of the animal
condensing , and afterwards hardening on its surface , and accordingly taking the figure of its body , which has performed the office of a mould to it ; in short , that the shell of a snail , and , as he supposed , of all other animals possessed of shells , was only the product of a viscous transudation from the body of the animal , containing earthl y particles united by mere juxtaposition . This hypothesis , however , is liable to very great and insurmountable difficulties , if we apply it to the formation of some of the most common shells : for how , according ; to this system , it may be asked , can the oyster , for instance ,
considered simply as a mould , form to itself a covering so much exceeding its own body in dimensions ? M . Iieris .-. ant * has discovered the structure of shells to be organical . In the numerous experiments that he made on an immense number , and a very great variety of animal shells , lie constantly found that they were composed of two distinct substances : one of which is a cretaceous or earthly matter ; and the other
appeared , from many experiments made upon it by burning , distillation , and otherwise , to be evidently of an animal nature . These two substances he dexterously separated from each other by a very easy chemical analysis ; by the gentle operation of which they were exhibited distinctly to view , without any material alteration from the action of the solvent , or instrument emplo . ed for that purpose . On an
entire shell , or a fragment of one , contained in a glass vessel , he poured a sufficient quantity of the nitrous acid , considerably diluted either with water or spirit of wine . After the liquor has dissolved all the earthy part of the shell ( which may be collected after precipitation by a fixed or volatile alkali ) , there remains floating in it a soft substance , consisting of innumerable membranes of a re iform appearance , and disposed , in different shells , in a variety of positions , which constitutes the animal part of it . This , as it has not been affected by VOL . ix , n
Note: This text has been automatically extracted via Optical Character Recognition (OCR) software.
A Brief System Of Conchology.
A BRIEF SYSTEM OF CONCHOLOGY .
THE singular regularity , beauty , and delicacy in the structure of the shells of animals , and the variety and brilliancy in the colouring of many of them , at the same time that they strike the attention of the most incurious observers , have at all times excited philosop hers to inquire into and detect , if possible , the causes and manner of their formation . But the attempts of naturalists , ancient and
modern , to discover this process , has constantly proved unsuccessful . M . de Reaumur hitherto appears alone to have given a plausible account , at least , of the formation of the shell of the garden-snail in particular , founded , on a course of very ingenious experiments , related in the Paris Memoirs . He there endeavours to show , that this substance is produced merely by the perspirable matter of the animal
condensing , and afterwards hardening on its surface , and accordingly taking the figure of its body , which has performed the office of a mould to it ; in short , that the shell of a snail , and , as he supposed , of all other animals possessed of shells , was only the product of a viscous transudation from the body of the animal , containing earthl y particles united by mere juxtaposition . This hypothesis , however , is liable to very great and insurmountable difficulties , if we apply it to the formation of some of the most common shells : for how , according ; to this system , it may be asked , can the oyster , for instance ,
considered simply as a mould , form to itself a covering so much exceeding its own body in dimensions ? M . Iieris .-. ant * has discovered the structure of shells to be organical . In the numerous experiments that he made on an immense number , and a very great variety of animal shells , lie constantly found that they were composed of two distinct substances : one of which is a cretaceous or earthly matter ; and the other
appeared , from many experiments made upon it by burning , distillation , and otherwise , to be evidently of an animal nature . These two substances he dexterously separated from each other by a very easy chemical analysis ; by the gentle operation of which they were exhibited distinctly to view , without any material alteration from the action of the solvent , or instrument emplo . ed for that purpose . On an
entire shell , or a fragment of one , contained in a glass vessel , he poured a sufficient quantity of the nitrous acid , considerably diluted either with water or spirit of wine . After the liquor has dissolved all the earthy part of the shell ( which may be collected after precipitation by a fixed or volatile alkali ) , there remains floating in it a soft substance , consisting of innumerable membranes of a re iform appearance , and disposed , in different shells , in a variety of positions , which constitutes the animal part of it . This , as it has not been affected by VOL . ix , n