720 PHILOSOPHICAL TRANSACTIONS. [ANNO 1800. 



complete solution of the whole was thus made, which, like that of the burnt alcy- 

 onium, yielded phosphate of lime; and at the same time the liquor became of an 

 orange colour, as soon as the ammonia was added. Some pieces of this alcyonium 

 were digested with boiling distilled water, and tinged it with a pale yellow colour. 

 Infusion of oak bark being then added, a large quantity of gelatin was precipi- 

 tated. The same pieces were boiled with lixivium of caustic potash, and when 

 dissolved formed animal soap. The calcareous part was separated during the 

 boiling, and subsided in the form of a fine powder. From the examination of the 

 few species of alcyonium which have been mentioned, it appears, that as the 

 sponges resemble the horny stems of gorgoniae, so these, in external and chemical 

 characters, resemble the fleshy or cortical substance which invests some of those 

 bodies ; and that they chiefly differ from the gorgoniae, by being destitute of the 

 horny stem, which in the latter seems to supply the place of bone. 

 § II. Observations on the foregoing Experiments. 



The simplicity and uniformity of the experiments here described, will not, I 

 flatter myself, render the facts less worthy of attention ; and I must 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 characteristics of 

 certain bodies appertaining to the animal kingdom, which hitherto had been but 

 little or not at all examined ; so that this outline, though defective, might serve 

 as a chain of connection, and as a basis, on which a more perfect superstructure 

 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 car- 

 bonate 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 though some other substances, as magnesia, silex, iron, with 

 some alkaline and neutral salts, might be occasionally 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 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 that the best mode of doing this, was 

 to compare and examine this substance in the various states in which it appeared, 

 when deprived of the hardening or ossifying matter. 



From what was said in the paper on shell and bone, concerning the substance 

 which remained after the carbonate of lime in shells, and after the phosphate of 

 lime in bones, had been dissolved and separated by weak acids, it is evident that 

 the substance which thus remains, is as various in relative quantity, as it is in 

 those qualities which apparently are produced by the degrees of natural inspissa- 

 tion, and by the progressive effects of organization. In the porcellaneous shells, 



