18 Mr. Warrington and Mr. Francis 



The one by M. Liebig, which supposes that the fat is pro- 

 duced by the conversion of sugar, starch and other non-ni- 

 trogenous bodies during the process of digestion, as detailed 

 in his paper on this subject published in the Society's Me- 

 moirs, vol. i. p. 164- ; a view which is supported by various 

 analogous processes and decompositions with which chemists 

 are already familiar, as for instance the conversion of amyg- 

 daline into the oil of bitter almonds, of salicine into oil of 

 meadow-sweet, and also the production of cenanthic aether in 

 the fermentation of amylaceous substances, which moreover 

 has recently been shown by M. Wohler to be readily con- 

 verted by distillation into margaric acid. The other theory by 

 MM. Dumas, Boussingaultand Payen*, according to which no 

 production of fat takes place in the animal frame, but that it is 

 contained already formed in the various products of the vege- 

 table kingdom, which generally serve the purposes of food. 



In support of this latter view, great importance has been 

 placed on some recent observations of M. Lewyfj communi- 

 cated to the French Academy of Sciences, in which it is stated, 

 that when purified bees'-wax is boiled with a concentrated so- 

 lution of caustic potash, or when cerine, one of the principal 

 constituents of wax, is heated with potash and lime at the tem- 

 perature of a metallic bath, it undergoes saponification, and 

 affords a combination entirely soluble in water, and from 

 which acids separate a fatty body having the properties and 

 composition of stearic acid. 



This statement, apparently so entirely at variance with what 

 had hitherto been published on the nature of this substance 

 and its behaviour towards the, alkaline bases, and the ease, 

 moreover, with which, if confirmed, pure stearic acid might 

 in future be obtained, induced us to repeat some of the ex- 

 periments of M. Lewy bearing on this point. 



Before, however, detailing the results at which we arrived, 

 it will perhaps be well to give in brief outline the data ob- 

 tained by former investigators. 



According to the researches of MM. Boudet, Boissenot J, 

 and Ettling§, wax is a mixture of cerine and myricine, which 

 may be readily separated from each other by means of alco- 

 hol, the myricine being nearly insoluble in that medium : the 

 cerine which is deposited on the cooling of the alcoholic solu- 

 tion is itself a compound body consisting of ceraine and mar- 

 garic acid ; these may be separated by treatment with caustic 



* Annates de Chimie et tie Physique, t. iv. p. 208. 

 f Comptcs Rendus, No. xiv. April 3, 1843, p. 675. 

 X Journ. de Pharin* vol. xiii. p. 43. 

 § Annalcn der Pharmacic, vol. ii. p. 253. 



