and Observations on the component Parts of Membrane. 357 



attention ; and I must again repeat, that the minutiae of analysis 

 did not form part of my present plan, which was only to sketch 

 an outline, comprehending the most prominent chemical cha- 

 racteristics of certain bodies appertaining to the animal king- 

 dom, which hitherto had been but little or not at all examined ; 

 so that this outline (although defective) might serve as a chain 

 of connection, and as a basis, upon which a more perfect super- 

 structure may in future be gradually raised ; and it appeared 

 evident, that this would be most easily and speedily executed, 

 by following a systematical and comparative plan. For this 

 reason, a great part of my attention was directed towards ascer- 

 taining, in these animal substances, the presence and general 

 proportions of carbonate and phosphate of lime ; these being 

 the materials essentially employed by nature to communicate 

 rigidity and hardness to certain parts of animals, such as shell 

 and bone ; and, although some other substances, as magnesia, 

 silex, iron, with some alkaline and neutral salts, might be occa- 

 sionally present in small proportions, (and indeed were at times 

 detected,) yet, as these appear to have but little influence on the 

 general characters of the bodies which were examined, I did not, 

 for the present, think proper to take particular notice of them. 



The next object was, to examine the nature of the substance 

 in and upon which the hardening or ossifying principles were 

 secreted and deposited ; and it seemed to me that the best mode 

 to do this, was to compare and examine this substance in the 

 various states in which it appeared, when deprived of the harden- 

 ing or ossifying matter. 



From what was said in the paper on shell and bone, con- 

 cerning the substance which remained after the carbonate of 

 lime in shells, and after the phosphate of lime in bones, had been 



