The solid crystalline fat No. 6 which was removed from the liquid 6o, and which was the most highly purified result from the crystallization of this specimen of adipocire, was now examined more particularly; an alcoholic solution was made upon which to try the different experiments. Fifteen grammes of the fat required 300 of alcohol of 93 per cent. to keep it in solution; but before having added so much alcohol, on standing for a short time 0.656 grammes of pearly crystalline scales fell, which had a melting point of 62.5°, and solidified at 55.5°. The fat of the liquid after these crystals had fallen, when precipitated by water, melted at 58°-61°, and solidified at 55.5°: these crystals, recrystallized from alcohol, melted at 62.5°, and solidified at 58°-57°; these were dissolved a third time, in twenty times their weight of 93 per cent. alcohol, which deposited, on standing, less than a milligramme of tufted crystals of the form of palmitic acid, of which it had the melting point 62°: more alcohol was added to the solution, and it was divided by fractional precipitation with acetate of magnesia and the addition of a little ammonia with heat, into two portions, weighing 0.256 and 0.164 grammes, and they had the same melting point. This fat appears, therefore, to be palmitic acid, one of the acids into which Heintz divided margaric acid. The crystals deposited from alcohol do not at all resemble those of margaric acid, but under the microscope are lamellar. These two fats were converted respectively, by an excess of nitrate of silver, into silver salts, 0·24725 gave 0·074 Ag. = 29·93 per cent. and 0·14275 gave 0·04175 Ag. = 29·25 per cent., which corresponds to the percentage of silver in the palmitate of this base.

C32192.00 By calculation. Mean of two Exper.
H3131.00
O432.00
Ag.107.9729.729.5
362.97

There is no doubt, therefore, of the presence of palmitic acid in the fat of human adipocire. The second crop of crystals which fell from the mother liquid of those just examined, contained a fat melting at 62°, in all probability palmitic acid also. A determination 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 electrical 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 ascertain 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 62.5°-63°.

[Transcribers Note: Missing text]precipitate the whole, was added; to the filtrate an excess of the magnesia solution was added, and the fat remaining in the filtrate from this precipitation was separated, as was also that of the other two precipitates. The following results and melting points are in their order as determined:

(a) 0·351 melts 61°
(b) 0·527 melts 61°
(c) 0·085 melts 53°
loss 0·173
1.136 grammes.

(a) and (b) were united, dissolved in alcohol, enough alcoholic solution of acetate of magnesia to precipitate the half added, and after standing for a couple of days, the precipitate was filtered off, and ammonia added to alkaline reaction to the filtrate. The first magnesia salt was translucent, and fused by heat to a transparent liquid, which by more heat gradually grew darker, finally black, and left a residue of magnesia. The melting point of the fat of this substance was as before, 61°.

The second magnesia salt was white and amorphous; it presented the same relations to heat as the first, and contained a fat of the same melting point, 61°. These fats were both brilliant white, lamellar, and of rough surface. The first magnesia salt contained a per centage of 7·59 MgO (0·25025 gave 0·019) and the second contained about double the per centage of magnesia, viz.: 14·91; for 0·28 salt gave 0·04175 magnesia by incineration.

Neutral palmitate of magnesia C32, H31, O3 MgO gives by calculation 7·6 per cent. magnesia, and basic palmitate C32, H31, O3 2 MgO gives 14·15 magnesia, which approaches the nearest to the magnesia salt of the above fatty acids.