and Observations on the component Parts of Membrane. 381 



are to be observed, in the same exact order, when a similar 

 piece of skin is exposed to putrefaction ; for this commences in, 

 and chiefly affects, the cutis, while the hair is separated, un- 

 changed in its quality. I do not, therefore, hesitate to assert, 

 that the degree of putrescibility in the various parts of animals, 

 depends principally on the presence, and on the quantity and 

 quality, of gelatin ; and the skin of the rhinoceros found 

 on the banks of the Vilui, near Yakutsk, was preserved, in all 

 probability, partly by the nature of the climate and soil, and 

 partly by the superior horny quality which it possessed over 

 other skins ; for it may be much questioned, whether the hide 

 of an ox or horse, in the same situation, would have escaped 

 putrefaction for so long a period.* 



From the preceding observations it appears, that gelatin is a 

 component part of many animal substances. 



That it differs in quality, from a very attenuated jelly or 

 mucilage, to that viscid substance called glue ; the varieties of 

 which also differ in solubility and tenacity. 



That it is present in various proportions; so that certain 

 bodies, such as the cutis, and the cartilages of the joints, are 

 formed by it ; while others, like nail, quill, and tortoise-shell, 

 can scarcely be said to contain it. 



And that, by its presence, in various states and proportions, 

 it may be regarded (including inherent moisture and organic 



* The more viscid gelatinous substances do not appear to be so immediately sus- 

 ceptible of putrefaction as those of the opposite quality ; for, when solutions, in water,, 

 of animal mucilage, eel-skin glue, and strong glue, were during a certain time ex- 

 posed under equal circumstances, I found the mucilage to be the first, and the glue the- 

 last, which shewed symptoms of putrefaction. 



