•Analysis of Shells. 361 



Art. X. — Analysis of Shells; by William B. Rogers, Prof, of 

 Chem. and Nat. Philosophy in William and Mary College, Va. 



I propose, at present, to give you a sketch of some analyses of the 

 recent oyster shell. The enquiry is one of some interest from the 

 importance which has hitherto been attached to the supposed pres- 

 ence of animal matter. The existence of this has been made a rea- 

 son among agriculturalists for anticipating peculiar benefit from the 

 application of oyster shells to the soil. Medical men have included 

 the preparations from testaceous shells among the articles of our 

 modern pharmacopeias, ascribing the conceived superiority of these 

 preparations in producing comparatively little irritation of the stomach 



to a considerable quantity of animal matter, thought to reside in the 

 shell. 



It will be seen by the following analysis, that the proportion of this 

 ingredient, is so minute, as to render it not worth estimating, either 

 when we compare the different modes in which the shell may be ap- 

 plied to the earth, on the different forms in which we may use it in 

 medicine. 



The subject is also one of interest to geologists as shewing, that 

 the absence of animal matter in fossil shells, is not to be ascribed in- 

 variably to fossilization, but may result in certain genera, from none 

 being contained in the recent state. 



Mr. Hatchett, the English chemist, was the first who undertook a 

 systematic investigation of the chemical composition of bones, shells, 

 and other analogous substances. He establishes the general result, 

 that, shells and bones, although greatly diversified in structure, may 

 be arranged into two distinct classes — both of them containing animal 

 matter — indurated in the one case, by carbonate of lime, and in the 

 other by phosphate. The shells of many marine animals, and sev- 

 eral zoophytes he found to occupy an intermediate rank, containin 

 animal matter, with variable proportions of both the calcareous salts. 

 The observations of this eminent experimenter appear in the main 

 to be correct — but in some of his details, especially in regard to the 

 oyster shell, he seems to have fallen into error. Murray, in his anal- 

 ysis of Hatchett's labors, speaking of the animal matter contained in 

 shells — remarks that, " this substance often constitutes a large part 

 of the shell, as in that of the oyster or muscle;" — a statement which 

 has since been disproved by the analysis of Bucholtz and Brandes, 



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