and Observations on the component Parts of Membrane. %99 



mentioned in the course of this paper, and which need not 

 therefore now be repeated, there can scarcely be any doubt but 

 that it is one and the same substance, in different states of den- 

 sity and texture. 



For the similarity of its nature was proved by, 



ist. The effects of fire, and the products obtained by distil- 

 lation. 



2dly. Its very difficult solubility by long digestion in boil- 

 ing water. 



3dly. The effects produced by re-agents, on the water in 

 which bodies like inspissated albumen or tortoise-shell had been 

 boiled. 



4thly. The effects of acids, (particularly nitric acid,) of am- 

 moniac, and of caustic lixivium of potash. 



5thly. The animal soap which was formed ; and the pre- 

 cipitate obtained from it, by the addition of acetous or muriatic 

 acid.* And, 



6thly. The difficulty attending the putrefaction of the sub- 

 stance in question, when pure and dense. 



The similarity in all these properties, appears to me a full 

 proof, that it is the same substance which constitutes the prin- 

 cipal part of membrane, sponge, horn, hair, &c. and even of 

 muscular fibre. 



Moreover, upon comparing the properties of this substance 

 with those of pure albumen in a state of inspissation, so evident 

 a resemblance in every respect is discovered, that few I believe 

 will hesitate to pronounce albumen to be the original substance 

 from which tortoise-shell, hair, horn, muscular fibre, &c. have 

 been derived and formed. 



■ This appears to be a strong marked character of the albuminous substances. 

 MDCCC. g F 



