They yielded an intense reaction of biliary acid; their properties and their bearing towards solvents made it likely that they consisted of glycocholic acid, but their quantity was not sufficient to institute a decisive examination. The concretion finally left a small quantity of a blackish matter, which was soft and flaky while moist, and on drying became humus-like. It principally consisted of organic matter, containing nitrogen, but only an insignificant amount of ash.

2. Fauconneau-Defresne (Rév. Méd.', i, 1841, and 'Mém. de l'Acad.', 13, 226) has described a kind of gallstones which he terms resinous calculi. They are easily friable, and after grinding form a yellowish-green powder, like ground aloes. They are almost entirely soluble in alcohol, ether, oil of turpentine, and alkalies. After extraction with ether there remains a small quantity of a smeary, white substance, possessing the properties of mucus. The ethereal extract, after filtration and evaporation, leaves a yellowish-green matter, which is transparent, without odour, and after drying can easily be powdered. By heat it fuses, forming a transparent fluid, and exhaling vapours of a balsamic odour, until it is at last transformed into a light charcoal. From these properties Garot concluded that the principal ingredient of these calculi was almost pure resin of the bile (Thénard's). It is highly probable that it was cholic acid, to the reactions of which those above related closely correspond.

3. An analysis of Orfila (Ann. de Chim.', 74, 34) yielded a certain quantity of picromel, combined with fat and colouring matter.

4. Caventou (Journ. de Pharm.', iii, 1817) also obtained picromel from a calculus weighing between twelve and thirteen decigrammes.

There are some notices of concretions alleged to have

consisted principally of inspissated bile. Buisson says that he observed some which came from the liver of an ox. In the human subject they have also been found, of a soft consistence, attracting moisture on exposure to air, possessing a very bitter taste, and having a higher specific gravity than cholesterine calculi. They are said to be soluble in water, alcohol, ether, and turpentine. The solubility in ether is, however, a circumstance which militates against their consisting of unaltered bile, and points to their probably containing principally cholic acid.

SIXTH SERIES.-Gall-stones with prevalence of Fatty
Acids.

1. Frerichs (2, 537) found margarate of lime to be the chief constituent of a human gall-stone contained in the museum at Goettingen, and examined by him in 1847.

It had an oval shape, a smooth surface, and a yellowishbrown colour; the surface of a fracture was of a resplendent white colour, and showed a radiary crystalline structure. In the centre there was a brown fissured nucleus, of the size of a lentil, and consisting of a compound of cholepyrrhine and lime and mucus. The white friable substance was only to a small part soluble in boiling alcohol and ether; the alcoholic solution, on evaporation, left plates of cholesterine, small balls, and needle-like crystals. The part insoluble in alcohol yielded to acetic acid much lime, and was then easily soluble in boiling spirit. The latter left crystalline scales of fatty acid. The melting point of this fatty acid was 58° C. (136° Fahr.). Neukomm determined it once more at 58.5° C. (137-3° Fahr.). The fatty acid from the gall-stone of an ox he found to fuse at 53° C. (127.4 Fahr.).

2. Calculus consisting principally of fatty acid.-This calculus was discovered in the collection of John Hunter, had by him been placed among the human urinary concretions, and was supposed to consist of the earthy phosphates. It was unaccompanied by any history, and it must therefore remain doubtful whether it was taken from the human subject or from one of the lower animals.

It was of dirty white colour, and had the greasy feel of cholesterine calculi; it floated on water, and when applied to the tongue left an impression of bitterness. It was of an oval figure, slightly flattened, one inch and a half in length, rather better than an inch in thickness, and about one inch and a quarter in breadth. It readily yielded to the knife, and the cut surface presented a polished appearance; its structure was lamellar, being composed of white and reddish-yellow layers, arranged concentrically and alternating with each other. The layers were easily separable; at its centre there was a small vacuity.

When heated before the blowpipe it readily fused, then caught fire, burning with a clear flame and giving out the smell of animal matter, but nothing of a urinous character. It left a carbonaceous residue, which, by raising the heat, was converted into a white ash. This ash was alkaline, dissolved in water and dilute acetic acid, and the solution gave a white precipitate with oxalate of ammonia; it was, therefore, lime.

When digested in boiling water, the water became slightly brown, and on evaporation a transparent, yellowishbrown residue was left, which had a bitter taste and consisted of inspissated bile.

Boiling alcohol extracted from it only a minute quantity of white, fatty matter, which was deposited on cooling.

A solution of caustic potass removed the whole of the colouring matter, but the rest of the calculus was unacted on; the potass solution was dirty green, and when neutralized with muriatic acid deposited a scanty precipitate, having the same tint.

When digested in nitric acid, effervescence took place, with the escape of a little nitrous acid; it then melted into a transparent oil, which, on cooling, concreted into a white, fatty matter. This substance, when washed with distilled water, melted at a temperature much below that of boiling

water.

When, instead of nitric acid, muriatic or acetic acid was employed, the portion of calculus did not melt until it had been removed from the acid; it then presented similar appearances to that obtained by the action of nitric acid; consequently this white, fatty matter was not formed by the action of the nitric acid.

In all these cases the acids retained lime in solution. The fatty matter, separated by the action of acids, was partially soluble in boiling alcohol, and the solution, on cooling, deposited shining, crystalline scales. With caustic potass it formed a ropy, almost gelatinous solution, and was precipitated in white flakes on the addition of an acid. A small piece being placed upon the ball of a thermometer previously heated, began to solidify when the temperature had sunk to about 135° Fahr.

From these experiments there could be no doubt that this calculus consisted of margarate or stearate of lime,

That the lime was in indicated by the in

mixed, probably, with the oleate of the same base and some of the other constituents of the bile. combination with the fatty acid was solubility of the calculus either in alcohol or caustic alkaline solutions until it had been previously digested in an acid.

To determine whether one or more of the fatty acids were present, the following analysis was made:

12.80 grs. of the calculus, previously dried in vacuo over sulphuric acid, were boiled in distilled water; a peculiar odour was given off, and the water acquired a yellowishbrown colour; being evaporated to dryness, it left a transparent, resinous-looking residue, which weighed 0.84 gr. This residue, when digested in alcohol, left 0.24, in the form of dirty yellow flakes, which in distilled water swelled up and ultimately dissolved, forming an imperfect solution which, in its chemical characters, exactly resembled that of the mucus of the gall-bladder.

The alcoholic solution being evaporated to dryness, the residue was redissolved in water; the solution was intensely bitter; with muriatic acid it gave a copious viscid precipitate; acetate of lead produced likewise a viscid cipitate, and the supernatant liquor, when clear, was again troubled by a solution of sub-acetate of lead.

pre

The 084 consisted, therefore, of-mucus of the gallbladder 0.24; inspissated bile, 0·60 gr.

After water had extracted from the calculus all that it was capable of dissolving, it was treated with successive portions of boiling alcohol, sp. gr. 830.

The first alcoholic solution, on cooling, deposited a white matter, which did not readily redissolve in hot alcohol or ether, but was acted upon by acetic acid. It appeared to be part of the calculus that had been dissolved unchanged; the quantity was, however, too minute to be estimated.