Adipocelluloses and Cutocelluloses 229 



These relationships have been more definitely made out by 

 Fre'my, in his investigations of the closely allied compound 

 which constitutes the epidermal or cuticular tissue of the leaves, 

 stems, &c., of Phanerogams. As the characteristic constituent 

 of cork is termed suberin, so Fremy terms this cuticular tissue- 

 substance cutin or cutose. To prepare this substance, the cuti- 

 cular tissue ('peel') of the apple, e.g., is treated with boiling 

 dilute acids, followed by digestion with the cuprammonium re- 

 agent (p. 10 ) ; then again with boiling acid, and dilute alkali 

 (KOH) ; finally the residue is treated with alcohol and ether. 

 In this way a nitrogen-free residue is obtained having the 

 empirical composition 



C . . . 73-66 p.ct. 



H . ii'37 ,t 



O . 14-97 



Not only by these results, but by the study of the proximate 

 resolutions of this substance it is shown to have the closest 

 relationships to the carbon compounds of the 'wax' class 

 (Compt. Rend. 48, 667). 



In a later investigation of the products of saponification of 

 this substance, Fre'my worked upon a raw material similarly 

 prepared, but having the composition C 68*3, H 8-9, O 22*8. 

 This compound is termed cutose, in substitution for cutin. 

 Cutose is slowly attacked by boiling alkaline solutions ; a pro- 

 duct is dissolved, of the same empirical composition as cutose 

 (comp. Lignocelluloses, p. 157), but of a fatty nature. It is pre- 

 cipitated on acidifying the solution ; the precipitate is soluble 

 in ether-alcohol, and when isolated is found to melt below 

 100. Under more drastic treatment with alkaline solutions 

 the dissolved products are found to be a mixture. Precipitated 

 by acids and treated with boiling alcohol the mixture dissolves ; 

 on cooling, the solution deposits an acid (m.p. 85) in yellow- 

 coloured flocks, which after fusion form a brownish translucent 



