and Observations on the component Parts of Membrane. 397 



of coal, from which, 1,50 grains of earthy residuum, obtained 

 by incineration, being deducted, the proportion of coal appears 

 to have been 54,50 grains. 



500 grains of dry albumen, afforded 74,50 grains ; and, as 

 the saline residuum amounted to 11,25 grains, the quantity of 

 mere coal was 63,25 grains. 



500 grains of tortoise-shell, yielded 80 grains of coal ; from 

 which, 3 grains of earthy matter being deducted, 77 grains 

 remain, for the proportion of coal. 



And 500 grains of the dry prepared muscular fibre of beef, 

 when distilled, left 108 grains of coal, which, by incineration, 

 afforded 25,60 grains of earthy residuum ; the coal may there- 

 fore be estimated at 82,40 grains. 



There appears much reason therefore to believe, that the 

 gelatinous substances and muscular fibre, differ from simple 

 and unorganized albumen, by a diminution of the carbonic prin- 

 ciple in the one, and by an excess of it in the other; and as, 

 in vegetables, the fibrous part is that which contains the largest 

 proportion of carbon, so, in respect to the other animal sub- 

 stances, muscular fibre appears to contain the greatest quantity 

 of it. 



The nature of the residua obtained by the incineration of the 

 substances lately mentioned, also deserves to be noticed. 



Only 1,50 grain was obtained from 500 grains of isinglass ; 

 and, as far as the quantity would allow, was proved to be 

 phosphate of soda, mixed with a very minute proportion of 

 phosphate of lime. 



The 3 grains afforded by tortoise-shell, consisted of phos- 

 phate of soda and of lime, with some traces of iron : it is 

 probable, that the latter was accidentally present. 



