358 Mr. Hatchett's Experiments on Zoophytes, 



dissolved and separated by weak acids, it is evident that the sub- 

 stance which thus remains, is as various in relative quantity, as 

 it is in those qualities which apparently are produced by the 

 degrees of natural inspissation, and by the progressive effects of 

 organization. 



In the porcellaneous shells, such as Cyprece, Sec. this substance 

 was proved to be much less in quantity than in those which 

 were afterwards mentioned ; and, although of a quality which 

 (like a cement or gluten) served to bind and connect the particles 

 of carbonate of lime firmly together, so small was the degree of 

 natural inspissation, and so little advanced was the degree of 

 organization, that when the carbonate of lime was dissolved, 

 even by very feeble acids, little or no vestige of jelly, mem- 

 brane, or cartilage, could be perceived ; nor indeed could any 

 be detected, but by the small portion of animal coal which was 

 formed, when these shells had been exposed for a short time to 

 a low red heat. 



But, proceeding from shells of this description to others tend- 

 ing to the nature of nacre or mother of pearl, (such as some of 

 the Patella,) a substance was left untouched by the acids, which 

 had the appearance of a yellowish transparent jelly.* So that 

 the substance which served merely as a gluten in the porcel- 

 laneous shells, was not only more abundant in these Patella, 

 but, being more inspissated, was become immediately visible 

 and palpable. 



In the common oyster, these qualities were more strongly 

 marked ; and, in the river muscle, and in the shells composed 



* The term jelly is here employed only to denote the degree of consistency of this 

 substance, which in its nature is very different from the varieties of animal jelly called 

 gelatin. 



