FATS. 273 



heated to 220 with hydrated potash, it hecomes converted 

 (see p. 72,) into cetylic acid (C 32 H 33 O + 2HO + KO = 4H + 

 KO.C 32 H 31 O 3 ). When warmed with concentrated sulphuric acid 

 it forms an acid haloid salt. 



Composition. According to the above formula, deduced from 

 the analyses of Dumas and Peligot,* this body consists of: 



Carbon 32 atoms .... 79'339 



Hydrogen .... 33 .... 13'636 



Oxygen 1 .... 3.306 



Water .... 1 3-?19 



100-000 



The atomic weight of the hypothetical anhydrous substance 

 = 2912-5. 



This body, like glycerine, is the hydrate of a fatty base ; but its 

 composition and its relations of combination indicate that it is 

 much more closely allied to the hydrated ethers or alcohols; in 

 common with them it is included in the formula C n H n+1 O.HO, 

 it loses the one atom of water in combining with acids, and is 

 converted by oxidation into an acid of the formula C n H n _ 1 O 3 . 

 Oxide of cetyl or cetylic ether in an anhydrous state has not been 

 obtained. 



Combinations. Very little is known of the acid sulphate of 

 oxide of cetyl in its isolated state. Its combination with potash, 

 which = C 32 H 33 O.SO 3 + KO.SO 3 is obtained in minute, thin, 

 nacreous plates. 



Cetylate of oxide of cetyl, C 32 H 33 O.C 32 H 31 O 3 (Smithf) ex- 

 ists preformed, under the name of cetin or spermaceti, princi- 

 pally in the cavities of the skull, but also in the fat of other 

 parts, of the Physeter macrocephalus. To obtain it in a state 

 of purity, we must repeatedly crystallise it from hot spirit, of 

 0'816 specific gravity. It separates in minute, nacreous, white 

 plates, devoid of smell and taste ; it fuses at 49, but on cooling 

 solidifies in a crystalline form ; it volatilises at 360 without decom- 

 position, dissolves in 40 parts of boiling spirit, of 0'821 specific 

 gravity, and more readily in anhydrous alcohol and ether ; when 

 submitted to dry distillation it yields no pyroleic acid, and when 

 digested v.'ith nitric acid it yields adipic but no suberic acid. When 

 heated with hydrated potash it is resolved into hydrated oxide of 

 Cetyl and cetylic acid. 



* Ann. d. Chim. et de Phys. T. 72, p. 5. 

 t Ann. d. Ch. u. Phavm. Bd. 42, S. 40-51. 



T 



