366 Mr. Hatchett's Experiments on Zoophytes, 



and the plan of the present paper, is considered, I flatter myself 

 that I shall not be censured as hasty or negligent, if at this 

 time I prefer a comparison of the chemical properties of the 

 bodies in question, with those of other substances, which (al- 

 though not elementary) may be regarded as primary animal 

 compounds ; and, when the subject is viewed in its full extent, 

 the mode which I have adopted will, perhaps, be deemed that 

 which is the most satisfactory. 



§. III. OBSERVATIONS ON THE COMPONENT 

 PARTS OF MEMBRANE. 



In relating the preceding experiments, I have had frequent 

 occasion to remark, that a quantity of that animal jelly which is 

 more or less soluble in water, and which is distinguished by 

 the name of gelatin, was obtained from many of the marine 

 bodies, such as the Sponges, the Gorgonice, and others ; but, in 

 the experiments made expressly to investigate the composition 

 of membrane, it still more frequently occurred ; and although 

 in many cases, either from the small quantity of the body 

 under examination, or from the very small portion of gelatin 

 thus obtained, I was obliged to content myself with ascertain- 

 ing the presence of it, by the test of the tanning principle, and 

 by nitro-muriate of tin ; * yet, in other experiments, when the 

 solutions of gelatin were gradually reduced by evaporation, I 



* Nitro-muriate of tin has been proposed as a test for the tanning principle ; and 

 the experiments contained in this paper prove, that it may also be employed with 

 much utility, to ascertain the presence of gelatin, and of certain modifications of 

 albumen. 



