16 ON ADIPOCIRE, AND ITS FORMATION. 
C3, 192.00 By calculation. Mean of two Exper. 
H;, ~—31.00 
O, 32.00 
Ag. 107.97 29.7 29.5 
362.97 
There is no doubt, therefore, of the presence of palmitic acid in the fat of human adipo- 
cire. The second crop of crystals which fell from the mother liquid of those just ex- 
amined, contained a fat melting at 62°, in all probability palmitic acid also. A determina- 
tion of the silver of the salt of this fat was lost in the following curious manner: The silver 
salt was in lumps, as it had dried on the filter, and after it had stood for a short time at 
100 in a watch glass, thinking to facilitate the escape of water, by pulverizing it in an 
agate-mortar, it became so exceedingly electric, that of the whole quantity of silver salt 
from 0.651 grammes of fat, I was not able to collect the smallest portion for analysis; 
whether the powder was attempted to be removed by steel, platinum, glass, a feather, or 
paper, on the first touch it flew into the air, and alighted upon the table: I have often 
noticed this behaviour in organic silver salts, and perhaps it would be worth while to try 
whether one of them could not favourably replace the amalgam on the cushion of the elec- 
trical machine. 
The following experiments were made upon the alcoholic solution of the fats, from which 
the above portions of palmitic acid were separated. Enough alcohol was added to this 
solution to prevent any further deposit by standing, for which, as was before stated, 300 
alcohol were required for 15 fat. Its percentage of fat was determined by evaporating the 
alcohol from a known quantity, and weighing the residue; the melting point of this fat 
was 60°5 to 61°. This melting point was again determined after saponification, to ascer- 
tain whether a fatty ether might not have been formed, and was found to be the same. 
The alcoholic solution of acetate of magnesia was also titled so that the necessary quantity 
might be added to the fat solution by measurement: the fat under consideration should be, 
by Heintz’s experiment, a mixture of stearic and the so called margaric acids, together with 
impurities. 
Before proceeding to the fractional precipitation by acetate of magnesia, the alcoholic 
fatty solution was treated with an excess of acetate of magnesia, and an excess of acetic 
acid (aided by a little warmth) added; the resulting liquid was then evaporated over 
sulphuric acid (removing the crystals as they formed) in order to ascertain what effect 
this treatment would have upon the melting points. On cooling, a small quantity of a 
powdery precipitate fell, and after standing for a couple of hours over sulphuric acid, the 
liquid crystallized rather suddenly, to plates or scales, the melting point of which, after 
treatment with acid, gave 62°; recrystallized from hot alcohol it melted at 62°95, 63°. 
