228 Cellulose 



teristic compounds, cerin and suberin. Cerin has the empiri. 

 cal formula C 2 oH 32 O. Suberin is of a fatty nature, and yields 

 stearic acid and phellonic acid (C 2 2H 4 2O 3 ) on saponification. 



In regard to the nomenclature of these compounds, we may, 

 consistently with the plan of this treatise, adopt the terms Suberose 

 and Cutose for the compound adipocelluloses as they occur in the 

 plant, and Suberin and Cutin for the non-cellulose groups united 

 to the cellulose to form the entire complex. 



This complex of substances has been further investigated 

 by Fliickiger (Arch. Pharm. 228, 690), who obtains glycerol as 

 a product of saponification, showing the presence of the more 

 ordinary glycerides of the fat acids ; he otherwise confirms, in the 

 main, the results of Kugler (supra]. Still more recently by C. v. 

 Wissenburgh (Chem. Centr. 1892, ii. 516) ; but the later results 

 throw no further light on the more important aspects of the 

 problem. These are obviously the questions of the constitu- 

 tion of the main tissue-substance and the physiology of its 

 formation, as well as that of the waxy excreted products which 

 accompany it. 



In suberose, as in cutose, it is to be noted that Fremy over- 

 looks the cellulose residue. V. Wissenburgh (loc. tit.} makes the 

 more positive statement that cork contains no cellulose. Both 

 observers appear to be in error on this point. 



There is some more conclusive evidence on these points in 

 the earlier work of Dopping and Mitscherlich. It is found 

 in effect that when rasped cork yielding to solvents 7-10 

 p.ct. of fatty constituents (supra) is oxidised with nitric acid, 

 it yields 40 p.ct. of fatty acids, and acids identical with those 

 obtained from the oxidation of fats and oils under similar 

 conditions, chiefly suberic acid. It is evident, therefore, 

 that the cork tissue is largely made up of constituents standing 

 in very close constitutional relationship to the natural fats and 

 oils, though possessing very different physical properties. 



