HYDROCARBONS 321 



tane (C35H72), is also a component of cactus, as well as of sugar cane wax 

 (Saccharum officinarum) .^^"^ n-Heptatriacontane (C37H76) has been shown 

 to occur in cactus. 



Pristane, CisHsg, is an example of a saturated hydrocarbon with a 

 branched chain, which has a wide distribution in liver oils of fishes. This 

 hydrocarbon was first separated from the hver lipid of the basking shark 

 by Tsujimoto'^^-'^^ in the amount of G to 10%. Toyama^^° suggested that 

 pristane is present to a small extent in most liver oils which contain squal- 

 ene; among the fish-liver oils which have been shown to contain pristane 

 are those from the liver of sardine, herring, and the sperm whale {Physeter 

 macrocephalus) .^*^ 



(h) The Presence of Compounds Related to Hydrocarbons in Plant and 

 Insect Waxes. In addition to hydrocarbons, primary alcohols, ketones, 

 and fatty acids have been demonstrated in plant and insect waxes, where 

 they are believed to be concerned with the intermediary metabolism. Some 

 of the products which have been observed are listed in the following sections. 



a'. Primary Alcohols: In contradistinction to the naturally-occurring 

 hydrocarbons, which usually are composed of odd-carbon chains, the 

 primary alcohols fomid in various plant and insect waxes consist of those 

 having an even number of carbon atoms. Thus, of the insect waxes, 

 honey-beeswax (Apis mellifica) is known to contain the C24-, C26-, C28-, 

 C30-, C32-, and C34-alcohols, while in lac wax from the shield-louse {Coccus 

 laccaY'^'^ alcohols having C26 to C36 have been observed. In Chinese insect 

 wax {Coccus ceriferus), the C26-, C28-, and C^o-alcohols are present. There 

 is also a wide distribution of the even-chain primary alcohols in leaf cuti- 

 cle waxes as shown below: carnauba wax, C26-C34; candehlla wax, C28-C34; 

 raphia wax and pisang wax (from the plantain, Alusa paradisiaca) , C28- 

 C32.^" Fruit and seed coat cuticle waxes consist of a large proportion of 

 these even-chain primary alcohols, as indicated by the composition of 

 apple cuticle wax (C26-C30) and cotton wax (C24-C34).^-- 



Cliibnall and Piper^- likemse recorded a high primary alcohol content 

 in non-cuticular leaf waxes, as follows: brussels sprouts, C26-C32; white 

 mustard, C28-C32; cactus, C06-C32; and wild white clo\'er {Trifolium repens), 



Cv28, Cv30. 



1" N. L. Vidyarthi and M. Narasingarao, J. Indian Chem. Soc, 16, 135-143 (1939). 



1^ M. Tsujimoto, Bull. Chem. Soc. Japan, 10, 144-148, 149-153 (1935); /. Chem. Soc. 

 /apan, 55, 702-741 (1934); Chem. Abst., 28, G-i8i{l93i). 



1" M. Tsujimoto, hid. Eng. Chem., 9, 1098-1099 (1917). 



!« Y. Toyama, Chem. Umschau Gebiete Fetle, Ole, Wachse u. Harze, SO, 181-187 (1923); 

 Chem. Abst., 17, 3616 (1923). 



"1 Y. Toyama and T. Tsuchiya, /. Soc. Chem. Ind. Japan, 38, suppl., 254-258 (1935). 



