702 



MARINE PRODUCTS OF COMMERCE 



used for leather. The first two in particular have a special structure of longitudinal 

 fibers in a compact layer of the outer dermis which gives a superior leather. The 

 skins of the other two are generally considered too thin and weak. At the close 

 of the last century $200,000 was roughly the annual value of "porpoise leather," 

 which was almost entirely from the white whale (q.v.). The hides were cut in a 

 right and left half, flensed, and salted. It is difiicult to distinguish in the accounts 

 of tanning and preparing of "porpoise" skins what species was under discussion; 



{Courtesy U. S. Fish and Wildlife Service) 

 Fig. 33-5. A school of blackfish on the shore of Cape Cod. 



in these cases it is perhaps well to consider it to have been the white whale, or 

 secondly the bottlenose dolphin, or both. The narwhal is not taken regularly, nor, 

 when taken, is used for its hide, which is turned into food by the Eskimo. 



Oil. Oils from cetaceans of all kinds fall into two chemical classes: glycerides 

 and waxes. Glycerides are compounds (esters) of 3 molecules of fatty acids and 

 1 molecule of the tribasic alcohol glycerol. The fatty acids are rarely the same; 

 generally two different kinds are attached (molecular ratio 2:1), and sometimes 

 three (1:1:1). Thus, in a glyceridic oil there are a number of glycerides involving 

 a number of fatty acids of carbon content, from 16 generally to as high as 22, but 

 only the single alcohol, glycerol, is present. Waxes on the other hand are com- 

 binations between 1 molecule of a fatty acid and 1 molecule of a higher monobasic 

 alcohol, such as cetyl or oleyl. The fatty acids usually vary from C^^ to CgQ. 

 Vegetable oils are glycerides, as are the tallows and fats from domestic animals. 

 Fat is the solid form of the same type of substance as oil, which is the liquid 

 form. Waxes also have liquid and solid forms. 



Glyceridic oils are found everywhere among the cetaceans. No fat-bearing 

 part of any species is without glyceridic oil, and the oil of most species and of 

 all baleen whales is exclusively this type. Waxes, on the other hand, are found 

 as the principal constituents of the oil of sperm, bottlenose, and beaked whales 

 only, and also occur in small amounts in the smaller species of dolphins and por- 

 poises which eat squid and dive deeply. 



Whale oil is the general term for the glyceridic oils from baleen whales, and 

 commercially may come from any one or several species mixed indiscriminately 



