ANALYTICAL EVIDENCE. 313 



The composition of the membrane lining the interior of 

 the shell of the egg approaches closely to that of horn. 

 According to Scherer, it contains 



Scherer.a 



Carbon 50*674 



Hydrogen 6*608 



Nitrogen 16761 



Oxygen ^ 



Sulphur' ' 



a Ann. der Chem. und Pharm., XL., 60. 



The composition of feathers is also nearly the same as 

 that of horn. 



Scherer.* a 



Beard of the Quill of the Calculated, 



feather. feather. C48HsN;Ol6. 



Carbon 50-434 52'427 52-457 



Hydrogen 7'110 7-213 6'958 



Nitrogen 17-682 17'893 17'719 



Oxygen 24'774 22-467 22-866 



The analysis here given of the beard of feathers agrees 

 closely with that of horn, while that of the quill is more 

 accurately represented by the attached formula, which dif- 

 fers from that of horn by 1 eq. of oxygen only. 



a Ann. der Chem. und Pharm. XL., 61. 

 7. COMPOSITION OF THE PIGMENTUM NIGRUM OCULI, 



Scherer.' a 



a Ann. der Chem. und Pharm., XL., 63. 



