by frank smith, b.sc, f.i.c., and l. a. meston. l;j 



The Oil. 



It is difficult to form any estimate of the amount of 

 oil produced bj^ prickly-pear in bearing. It is urged, how- 

 ever, that the oil from the low percentage present in the 

 seed, and on account of the nature and mode of distri- 

 bution of the latter, can have no commercial value, and the 

 present communication must be viewed merely in the light 

 of a contribution to the chemistry of opuntia spp. 



For the purpose of investigation a quantity of prickly- 

 pear seed was collected for us by Dr. Jean White, of the 

 Dulacca Prickly Pear Experiment Station, to whom our 

 thanks are due. The oil was removed by petroleum spirit 

 and the solvent removed by evaporation, finally in a brisk 

 stream of carbon dioxide. 



The oil is of a clear amber colour, and on examina- 

 tion was found to have the folloAving constants : — 



Sp. gr at 15715° C .9242 



Refraction (Zeiss at 20° ('.) . . . . 74.8 



(Abbe at 20° ('.) . . . . 1.475 



(Oleo at 22") -J- 26 



Acid Value . . . . . . . . 2.8 



Saponification Value . . . . . . 187.5 



Iodine Value (Hiibl) 130 



Bromine-thermal Value . . . . . . 24.2 



Hehner ^'alue . . . . . . . . 04.!! 



Reichert-Meissl ^'alue . . . . . . .4 



The Fatty Acids. 



The mixed fatty acids were found to have an iodine 

 value of 133, and a neutralisation value of 201. The mean 

 molecular weight is 279. 



The liquid and solid acids composing the mixed fatty 

 acids were separated by the usual method of taking advant- 

 age of the different solubilities of their lead-salts in ether. 



The mixed fatty acids consist approximately of (1) 

 83 per cent liquid acids : (2) 17 per cent, of solid acids. 



The Liquid Fatty Acids. 

 The iodine value of the liquid acids was found to l)e 

 136, and the mean molecular weight 283. The oxidation 

 products by the alkaline permanganate method of Hazura 

 and Griissner were examined. Typical crystals of dioxy- 

 stearic acid, melting at 130° C. and crystals of an isomer 

 of sativic acid (tetroxystearic acid), M.Pt. 156-159'' C. 



