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crystals, and (ii) in prismatic crystals. The first, obtained by crystallisation from alcohol, acetone, ether (of which it requires 510 parts at 18° for solution), isobutyl alcohol, or ethyl acetate, has the formula C25H2O+ HO. It only loses this water of crystallisation at or above 145°, and partial decomposition always takes place simultaneously. Fusion ultimately results at 160-180°. The prismatic crystals, obtained by the precipitation of an acetic solution of the acid with water, have the formula C25H2O5 + H2O. They lose mol. H2O at 120°, but the remaining is only lost at or above 145°. The author believes Mylius to have taken the not fully dehydrated acid as anhydrous. When this acid is dissolved in phenol, it forms white prisms, which give analytical results, agreeing with the formula С25H12O5 + H2O + CHO. It seems that the last trace of water is very firmly united to the cholic acid, and that when crystallised from other media with which it unites, the acid only takes up the complementary quantity of the medium. Thus the crystals from an alcoholic solution had the formula CesH2O + H2O + C2H2O.

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Attempts to obtain mineral salts of the acid showed that here also a similar state of things existed. The salts all contained an excess of the base, that excess being, as in the case of the water of crystallisation, about one-eighth of an equivalent. With aniline and toluidine, however, cholic acid yields well-defined crystalline salts, which give numbers agreeing with those required by theory. Aniline cholate, C2H2O,NH2Ph, forms needles melting at 140°; metatoluidine cholate needles melting at 140-180°. L. T. T.

Action of Sodium Chloride in Dissolving Fibrin. By J. R. GREEN (J. Physiol., 8, 372—377).—When fibrin is extracted with a 5 or 10 per cent. solution of sodium chloride, a proteïd goes into solution; on renewing this solution daily, removing that added on the previous day, it is found that in 32 to 35 days the whole of the fibrin is dissolved. In all these experiments, there was perfect freedom from putrefaction. When dissolved in this way, the fibrin is decomposed, with the formation of two globulins, one of which coagulates at 56°, is soluble in 1 per cent. sodium chloride solution, is readily converted into syntonin and alkali-albumin, and is not precipitated by weak acid; the other is insoluble in 1 per cent. sodium chloride solution, but soluble in a 10 per cent. solution; it coagulates on heating at 59— 60°, is readily converted into alkali-albumin, but not into syntonin, the acid added for the latter purpose precipitating it, and in suspension it is not acted on. In some of its reactions, the former substance recals the behaviour of fibrinogen, but neither corresponds with fibrinogen or serum globulin, and the latter cannot be made to re-form fibrin. W. D. H.

Hæmatoporphyrin. By C. A. MACMUNN (J. Physiol., 8, 384— 389).-A brownish pigment is scattered over several superficial portions of the mollusc Solecurtus strigillatus. On microscopical examination, it is found that, in the foot especially, the pigment is situated at the border of the cells, so that the boundaries between them are marked much in the same way that endothelium cells are

demonstrated by the use of silver nitrate. Granules in the cells contain the same pigment. Spectroscopic examination shows that the pigment is hæmatoporphyrin; this is identical with Moseley's polyperythrin (Quart. J. Mic. Science, 17, 1); the bands are identical with those seen in the pigment from the dorsal streak of the earthworm; a list of 12 other invertebrates in which the same pigment has been found is given. In many of these there is no hæmoglobin present, but the universal distribution of the histohæmatins, and the fact that these yield some of the decomposition products of hæmoglobin, fully explain the occasional appearance of a hæmoglobin-derivative in invertebrate animals (see Abstr., 1886, 638). W. D. H.

Physiological Chemistry.

Influence of Sleep on the Activity of Respiratory Combustion. By L. DE SAINT-MARTIN (Compt. rend., 105, 1124-1128).— Experiments with doves show that, independently of the effect produced by fasting, natural sleep reduces the quantity of carbonic anhydride exhaled by about one-fifth, and reduces the quantity of oxygen absorbed by about one-tenth.

Experiments with dogs show that during sleep produced by morphine the proportion of carbonic anhydride exhaled falls to one-half the normal amount; during sleep produced by chloral or chloroform it falls to one-third the normal proportion.

When anesthesia by chloroform is sufficiently long continued the blood becomes impoverished in oxygen and is charged with an amount of carbonic anhydride very considerably in excess of the normal proportion. In the early stage of insensibility, there is a diminution in the proportion of carbonic anhydride in the blood, but this is due to secondary causes. C. H. B.

Coagulation of Fibrin and Intravascular Clotting. By F. KRÜGER (Zeit. Biol 24, 189-225).-Wooldridge has shown that the phenomenon of coagulation is brought about by a substance which he calls A fibrinogen, obtainable from peptone plasma by simply cooling, and that the cellular elements which were hitherto considered essential, although they may assist coagulation, are nevertheless of secondary import. In his Croonian lecture he described coagulation as essentially similar to crystallisation. In plasma there are three constituents concerned in coagulation-A, B, and C fibrinogen. A and B fibrinogen are compounds of lecithin and proteid, and fibrin results from the transference of the lecithin from A fibrinogen to B fibrinogen. From this point of view the ferment is of secondary import

ance.

Wooldridge further found that a compound of lecithin and proteïd closely allied to the A fibrinogen, which he considers probably the

precursor of A fibrinogen, exists in the testis and thymus gland of the calf, in the fluid of the lymph glands and the stromata of red bloodcorpuscles. This compound is capable of causing widespread intravascular clotting in the entire absence of any cellular elements.

It is with reference to this last statement that the author joins issue. A large number of experiments have led him to the opposite conclusion, namely, that the corpuscular elements play the chief part in the coagulation, both within and without the body. He corroborates Wooldridge's statement, however, that the stromata of red blood corpuscles produce intravascular clotting.

The leucocytes obtained by centrifugalising the fluid of the lymph glands produce intravascular clotting, but the supernatant liquid, the author states, is inert, or almost so. He considers that any slight action of the fluid may be accounted for by the presence of some leucocytes, for he found it impossible to remove them completely, even by centrifugal action. J. P. L.

Influence of Calcium Sulphate on the Coagulation of the Blood. By J. R. GREEN (J. Physiol., 8, 354-371).-A saline extract of washed blood clot contains fibrin ferment (Buchanan). Heating such an extract nearly to the boiling point delays the action of the ferment but does not destroy it; the ash was found to contain a definite and fairly constant amount of calcium sulphate. A saturated solution of calcium sulphate was prepared, and on adding 1 c.c. of this to 10 c.c. of diluted magnesium sulphate plasma, coagulation set in with great rapidity; a very small amount of the salt (0·001 per cent.) has considerable clotting power; this increases with the quantity of calcium sulphate used, but not proportionately. In other experiments with peptone or leech extract, in which coagulation was retarded by cold, the addition of calcium sulphate caused it to take place in some cases very rapidly, in others more slowly.

Calcium sulphate cannot be regarded as the fibrin ferment however; addition of that salt to pericardial fluid or to a sodium chloride solution of fibrinogen causes no coagulation in those fluids; but when the ferment is present, addition of salt accelerates the coagulation.

The next point investigated was whether it is possible to have coagulation in the absence of calcium sulphate; peptone-plasma was dialysed for three days into a 06 per cent. solution of sodium chloride; if water had been used outside the membrane, the globulins of the plasma would have been precipitated. Dilution of the plasma with saline solutions then caused no clotting, nor did the passing of a stream of carbonic anhydride through the plasma coagulate it as it does ordinary peptone-plasma. But on adding a little calcium sulphate to the diluted plasma coagulation rapidly set in.

In plasma prevented from coagulating by cold, or by admixture with magnesium sulphate, similar experiments were performed, dialysis being carried out at the temperature of 1°. After a week's dialysis, dilution caused no coagulation, but after adding calcium sulphate clotting set in, though slowly. It was suggested that the fibrin ferment exists as a zymogen in plasma, and is converted into ferment by the action of calcium sulphate. Horse's blood kept from

clotting by cold was precipitated by a large excess of alcohol; after remaining for some weeks under the spirit, the precipitate was collected, dried, and extracted with a 0·6 per cent. sodium chloride solution; this was warmed with calcium sulphate for an hour, and then that salt removed by dialysis; but on diluting plasma or pericardial fluid with this there was no hastening of the coagulation; that is, there was no evidence of zymogen conversion.

Calcium sulphate helps the working of the ferment, but it is not concerned with its liberation. Quantitative experiments on the relation of the amount of fibrin formed to the amount of calcium sulphate added negative the idea that fibrin is a union of fibrin with that salt. Hammarsten (Maly's Jahrsbericht, 4, 135) has shown that calcium phosphate is necessary for the proper activity of the rennet ferment. W. D. H.

Secretion of the Gall Bladder. By B. BIRCH and H. SPONG (J. Physiol., 8, 378-383).—The fluid was obtained from two women in which a fistula remained in each case after the operation of cholecystotomy had been performed. A celluloïd cannula was found to be the best to use, as it did not set up the irritation consequent on the use of metallic ones. About 20 c.c. in the day was collected, but it is supposed that a third or more of the fluid was lost. In both cases the bile channels were completely closed off from the gall bladder, and no biliary constituents were present. The fluid was therefore the secretion of the mucous membrane of the gall bladder, and in both cases it had identical composition and properties. Both patients were also in excellent health. The fluid was sometimes clear, sometimes faintly opalescent; it was viscid; its specific gravity varied from 1.011 to 1.012 at 12.5°. On microscopic examination, it was found to contain a few leucocytes. It was always distinctly alkaline, which reaction must be attributed to alkaline sodium phosphate. The following is the approximate quantitative analysis in parts per 1000:

The fluid has distinct diastatic properties, which were destroyed by boiling; the fermentation agent was not definitely separated; the

alcoholic precipitate, however, was found to contain it, whilst none remained in the filtrate; the ferment was also non-diffusible. Some was filtered through a porous cell; the filtrate was inoperative on starch, whilst the residue, which evidently represented the mucin that could not get through the filter, was still active. The fluid had no curdling action on milk, and no emulsion was formed when it was mixed with cod-liver oil. The secretion, moreover, does not readily putrefy, although it was demonstrated by means of experiments with sterilised peptone infusion that it has no active power in restraining putrefaction; its apparent immunity from change being due to its poverty in nourishing material. The secretion cannot be regarded as playing any important part in digestion, the small diastatic action it possesses being shared by many fluids in the economy on which it does not confer any special digestive value. Its use is no doubt confined to lubricating the walls of the gall bladder, and it adventitiously adds some mucus to the bile which comes to repose in it.

W. D. H.

Analyses of American Fishes. By W. O. ATWATER (Amer. Chem. J., 9, 421-452).—52 species of American fishes were examined. The methods of analysis are described, and tables are given containing proportion of edible portion and the amounts of nitrogen, proteïds, ether extract, and ash of this portion of the fish. The composition varies very considerably, thus

Ferments in Normal Urine. By E. STADELMANN (Zeit. Biol., 24, 226-260). Very divergent opinions have from time to time been expressed with reference to the presence of ferments in normal urine. It may be safely said that all observers are agreed on the constant occurrence of pepsin in normal urine, but the most conflicting evidence is forthcoming as to the presence of trypsin.

Grützner and his pupils, Sahli, Gehrig, and Holovtschiner state that trypsin is a constant concomitant of normal urine, and that it is present in regular quantity. Mya and Belfanti state that both pepsin and trypsin are present in normal and pathological urine, except in cases of acute and chronic nephritis.

In opposition to this, Leo denies the occurrence of trypsin in all cases, but admits the presence of pepsin in normal and in most pathological cases. In cancer of the stomach and typhoid fever, pepsin, is however, absent.