[ 130 ] 



XX\'U.Me77ioi}- on the Nature of fat Suhstances. By Henry 

 Braconnot, Professor of Natural History, and Director of 

 the Garden of Plants at Nunci. 



M, 



[Concluded from p. 41.] 



Action of the Nitric Acid upon Suet. 



LE5SRS. Fourcroy, Alyon, and Vogcl have already made some 

 experiments on the action of tlie nitric acid upon fat; but these 

 chemists seem to have considered the results of this action onlv 

 as furnishing a medicament, wliich has been called, with sufficient 

 impropriety, oxygenated pomatum ; for, to speak the truth, this 

 fat cotitains suet ;.pj)roaching the state of adipocire, fixed oil 

 with nitric and acetic acids combined with these fat matters. 



Twenty grammes of beef suet were put into a retort, and there 

 ■were added 120 grammes of the nitric acid of commerce at 39'. 

 The reaction between these two substances was not so prompt 

 as might have been expected ; for the acid was in full ebullition 

 without any red vapours being extricated: at length the latter 

 appeared, and distillation was continued until almost the whole 

 of the acid had passed over: there was extricated but a small 

 quantity of azotic gas mixed with carbonic acid, and a volatile 

 oil which had the smell of coriander. 



The suet thus altered and remaining at the bottom of the re- 

 tort was melted several times in boiling water ; the water was 

 uniformly set apart: and we shall examine them presently. In 

 the mean time we direct our attention to the fatty substance 

 which refused to melt in boiling water ; this weighed 13 grammes, 

 had an acrid styptic taste, partly owing to the nitric acid which 

 it still retained : it was much softer than the suet employed, and 

 contained a quantity of fixed oil of a brown colour, very soluble 

 in alcohol, besides a solid substance which was isolated from the 

 oil by pressure in gray paper. This concrete substance was dis- 

 solved in a small quantity of warm alcohol ; the mixture became 

 hard on cooling; it was then pressed in gray paper, and a snow- 

 white substance was obtained in fine needles of a pearly appear- 

 ance : it is inodorous, not very sapid, pulverulent, soft and unc- 

 tuous to the touch, precisely like spermaceti ; but it is infinitely 

 more soluble in warm alcohol, which takes up such an immense 

 quantity that the liquor runs into a solid mass upon cooling. If 

 the solution be sufficiently diluted with alcohol, snowy-like flakes 

 are precipitated, formed of a net-work of very fine needle-like 

 crystals. Ether and oil of turpentine also dissolve perfectly this 

 substance, which crystallizes by the spontaneous evaporation of 

 those solvents. It docs not experience any sensible alteration 



from 



