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The above results point to the following three formulæ for cholic acid, dehydrocholic acid, and bilianic acid respectively :


COOH C20H3(CH2OH),: CH·OH; COOH C20H31 (CHO)2: CO;

Cholic acid does not contain an aromatic nucleus, and the readiness with which it is destroyed by oxidation makes it improbable that any other closed-chain nucleus is present. N. H. M.

Myohæmatin. By C. A. MACMUNN (Journ. Physiol., 8, 51-65). -Myohæmatin can be obtained in solution by extracting the muscles which contain it with ether. As a result of osmotic phenomena, a muscle juice exudes, and floating above it is the ether which, if the muscles of pigeons be used, contains in solution a yellow lipochrome. The muscle juice itself is of a red colour, and gives the spectrum of modified myohæmatin, which is not altered by a stream of either oxygen or carbonic acid. The juice is acid in reaction, and contains various proteïds, in addition to the myohæmatin, and also creatin, which crystallises out on evaporation. W. D. H.

Physiological Chemistry.

Sensitiveness of the Sense of Smell. By E. FISCHER and F. PENZOLDT (Annalen, 239, 131-136).-The authors find that 1 vol. of mercaptan vapour in 50,000,000,000 vols. of air is clearly perceptible to the sense of smell, and 1 vol. of chlorophenol in 1,000,000,000 of air; or it is possible to detect by their odour 60,000 mgrm. chlorophenol and 0.000.000 mgrm. mercaptan.

W. C. W.

New Constituent of Blood-serum. By L. C. WOOLDRIDGE (Proc. Roy. Soc., 42, 230—232).—A very small quantity of a proteïd substance, serum-fibrinogen, can be obtained by rendering undiluted serum distinctly acid by means of dilate acetic or sulphuric (4 per 1000) acid. It is constantly present in the serum of dog's and sheep's blood, but absent from that of the horse and ox. In physical characters, it resembles fibrin, but is more readily soluble in dilute alkali than that substance. It is totally different from paraglobulin, and is interesting in view of Schmidt's theory that two proteïds are necessary for coagulation; it was perhaps an admixture of this substance with paraglobulin that led Schmidt to suppose that the latter substance is one of the two necessary proteïds. On adding a solution of serum fibrinogen to peptone plasma, coagulation is brought about in a few minutes. After injecting it into the circulation, the shed blood remains-uncoagulated for many hours. It has an extremely feeble influence on magnesium sulphate plasma, and hence contains but a trace of fibrin ferment. W. D. H.

Muscle Plasma. By W. D. HALLIBURTON (Proc. Roy. Soc., 42, 400-401). The facts described by Kühne relating to the properties of the muscle plasma of cold-blooded animals are true in great measure for that of mammals.

Admixture of muscle plasma with solutions of neutral salts prevents the coagulation of the latter. Dilution of such salted muscle plasma brings about coagulation; this occurs most readily at 37-40°. Saline extracts of rigid muscle differ from salted muscle plasma in being acid, but resemble it very closely in the way in which myosin can be made to separate from it; myosin in fact undergoes a recoagulation. This is not a simple precipitation; it is first a jellying through the liquid; the clot subsequently contracts, squeezing out a colourless fluid or salted muscle serum. This does not take place at 0°; it occurs most readily at the temperature of the body, and is hastened by the addition of a ferment prepared from muscle in the same way as Schmidt's ferment is prepared from blood. The ferment is not identical with fibrin ferment, as it does not hasten the coagulation of salted blood plasma; nor does the fibrin ferment hasten the coagulation of muscle plasma. The recoagulation of myosin is also accompanied by the formation of lactic acid.

The proteïds of muscle plasma are-1. Paramyosinogen, which is coagulated by heat at 47°. 2. Myosinogen, which is coagulated at 56°. It is on the presence of this proteïd that the power of fresh muscle juice to hasten the coagulation of blood plasma depends. 3. Myoglobulin, which differs chiefly from serum globulin in its coagulation temperature (63°). 4. Albumin, which is apparently identical with serum albumin a, coagulating at 73°. 5. Myo-albumose; this has the properties of deutero-albumose, and is identical or closely connected with the myosin ferment. The first two proteïds in the above list go to form the clot of myosin; paramyosinogen is, however, not essential for coagulation; the three last remain in the muscle serum.

Paramyosinogen, myosinogen, and myoglobulin are proteïds of the globulin class. They are all completely precipitated by saturation with magnesium sulphate, or sodium chloride, or by dialysing out the salts from their solutions. They can be separated by fractional heat coagulation, or by fractional saturation with neutral salts.

When muscle turns acid, as it does during rigor mortis, the pepsin which it contains is enabled to act, and at a suitable temperature (35-40°) albumoses and peptones are formed by a process of selfdigestion. It is possible that the passing off of rigor mortis, which is apparently due to the reconversion of myosin into myosinogen, may be the first stage in the self-digestion of muscle. W. D. H.

Fermentation by Protoplasm from Recently Killed Animals. By FOKKER (Compt. rend., 104, 1730-1732).-If a small quantity of any organ of a recently killed animal is taken, with all precautions to prevent access of bacteria, and is placed in a sterilised fluid and gently heated, it can convert sugar into acid and starch into glucose: but careful examination by means of the microscope and by cultivation, fails to show the presence of any microbes.

When an acid is produced, the change ceases after a short time, because the acid formed arrests the action of the protoplasm. If, however, the liquid is carefully neutralised, the change recommences, and will continue for several months if the liquid is kept neutral. The quantity of acid produced by the protoplasm is smaller than would be formed under the same conditions by the action of microbes. The difference between protoplasm from a healthy animal and microbes lies mainly in the tendency of the latter to multiply. The only alteration which the tissues undergo during the fermentative changes which they produce, is the destruction of the nucleus.

C. H. B.

Action of Caffeïne and Theïne on Voluntary Muscle. By T. L. BRUNTON and J. T. CASH (Proc. Roy. Soc., 42, 238-239).—Both caffeïne and theïne cause rigor in the voluntary muscles of frogs; in the same frog, the stronger the solution used the more powerful is the action; although a large dose will often cause less action in one frog than a smaller one will cause in another. Theïne is rather more powerful than caffeïne; theïne, moreover, tends to produce rhythmical contractions in the muscle. The addition of lactic acid or chloride of calcium aids, whilst potash diminishes the action of the alkaloïds. W. D. H.

Chemical Constitution and Physiological Action. By T. L. BRUNTON and J. T. CASH (Proc. Roy. Soc., 42, 240). The distinctive action of the lower members of the fatty series is their stimulant and anaesthetic action on the nerve centres. The members of the aromatic series also affect the nervous system-especially the motor centres, producing convulsions and paralysis. Benzene, chlorobenzene, bromobenzene, and iodobenzene are similar in their action on frogs, the halogen radicles not modifying the action of the benzene to any great extent. The introduction of hydroxyl into the benzene nucleus intensifies the convulsant action. W. D. H.

Diabetes and Glycerols. By W. B. RANSOM (Journ. Physiol., 8, 99-116). The following conclusions are drawn from experiments on rabbits :-(1) That certain forms of glycosuria-for instance, that produced by puncture of the medulla oblongata, may be checked by glycerol; (2) that glycerol acts more efficiently when introduced into the alimentary canal than when injected subcutaneously; (3) that glycerol checks glycosuria by inhibiting the formation of sugar in the liver; (4) that in this way it may lead indirectly to an accumulation of glycogen in the liver. Viewing the formation both of glycogen and sugar as a process of cell metabolism, quite independent of ferment action, it is impossible to suppose that glycerol produces its effect by acting on a ferment in the blood, but more probably it exercises some direct influence on the protoplasm of the liver cells. The usual theory of a ferment which comes especially into play after death and changes the glycogen in the liver into sugar is considered untenable; and the post-mortem formation of sugar is regarded as being due to metabolism still going on in the cells of the liver which retain their vitality for some time after the heart has stopped.


W. D. H.

3 u

Lævorotatory ß-Hydroxybutyric Acid in the Blood of a Diabetic Patient. By L. HUGOUNENQ (Bull. Soc. Chim., 47, 545–546). -Lavorotatory B-oxybutyric acid has been recognised in the urine of diabetic patients; the author has now detected its presence in the blood. The process used for its identification was as follows:-The blood was kept in contact with ether until the sugar present had been removed; it was then evaporated to dryness on the water-bath, and the solid coagulum exhausted with boiling water; the extract was precipitated with basic lead acetate and ammonia, and the filtered solution examined in the polariscope when the presence of the acid was indicated by its lavorotatory action. A second portion of the blood was then taken, evaporated, and extracted with water as in the first case, the aqueous solution evaporated almost to dryness, and the product treated with an equal volume of sulphuric acid and distilled; on fractioning the distillate, and treating the fractions with a freezing mixture, crystals separated which, after recrystallising from ether, were recognised as crotonic acid by the melting point (70-71°), this acid having been formed by the dehydration of B-hydroxybutyric acid. According to the results obtained by Külz (who found the rotatory power of B-hydroxybutyric acid to be -234°), the author found the blood contained 4:27 grams of the acid per litre, the urine of the same patient containing 4:48 grams per litre.

A. P.

Does Human Urine contain Free Acid ? By E. BRÜCKE (Monatsh. Chem., 8, 95—100).—The theory generally accepted of the cause of the acidity of urine is that it is due to the presence of the acid phosphate of sodium or potassium in that secretion. E. Salkowski (Lehre vom Harn, Berlin, 1882, 15) leaves the question open as to whether hippuric acid which is present in small amount, is free or combined. The present research consists of experiments with congo-red, the colour of which is changed by acids. One part of hippuric acid dissolved in 55,000 of distilled water free from ammonia, causes a solution of congo-red to become violet or inky in colour. Hippuric acid does not appear however to be present in urine, and no urine hitherto examined produces any change on congo-red.

If to a solution of that pigment, a few drops of dilute sulphuric, phosphoric, or hydrochoric acid be added, the liquid assumes an inky tint. If this mixture is dropped into urine, each drop becomes red again, or if the urine be first coloured with congo-red, and acid added drop by drop, the cloud caused by the first drops redissolves: so that one cannot use this method for titration. If more acid is added, a precipitate of a rust-red colour in which the pigment is fixed settles, and the urine can be filtered off having its normal colour. The use of congo-red paper is hardly more satisfactory. If the paper be coloured violet by phosphoric acid, it is found that a solution of sodium chloride will render it red. This cannot wholly depend on the unequal diffusion of acid and base. A solution of congo-red rendered violet by hydrochloric acid is also made red by sodium chloride this is probably not due to a union of the sodium chloride with the acid, but perhaps to a raising of the refractive index of the mixture, and a molecular alteration of the pigment. The colour is


browner than that produced by acids. If the solution of the pigment and sodium chloride be added to urine, it dissolves with a bright red colour. These facts teach that the bases in urine are not so far saturated with acids that the addition of more acid necessarily involves the presence of free acid. Whether the bases are metallic or not must be ascertained by future investigation; urea certainly has no effect on a solution of the pigment rendered violet by acid.

Carbonic acid is also not free in the urine, for congo-red is easily affected by that acid. In certain circumstances, free uric acid is sometimes present in urine in a crystalline form; but in such urine congo-red also shows that there is no free uric acid in solution at the same time. W. D. H.

Chemistry of Vegetable Physiology and Agriculture.

Reduction of Silver Salts by Living Protoplasm. By T. BOKORNY (Ann. Agronom., 13, 239-240).-The blackening of argentic nitrate by the protoplasm of living cells, discovered some years ago by the author and Loew, has been attributed by Beaumann and Hoppe-Seyler to the action of hydrogen peroxide. The author finds, firstly, that hydrogen peroxide cannot be detected in the living cells of Spirogyra by any test, secondly, that dead cells of Spirogyra even after imbibing a 10 per cent. solution of hydrogen peroxide, will not effect the reduction. J. M. H. M.

Changes in the Proteïds of Seeds during Germination. By J. R. GREEN (Proc. Roy. Soc., 41, 466–469).— Gorup-Besanez (Ber., 1874, 1478) stated that the changes in the reserve proteïd materials during germination are probably due to the action of a proteolytic ferment. This was disputed by Krauch (Abstr., 1878, 996). The present experiments demonstrate in the case of the seeds of the Lupinus hirsutus, the correctness of Gorup-Besanez' view. The seeds were allowed to germinate for about a week; they then gave an acid reaction to test-paper; the cotyledons were ground, extracted with glycerol, and the extract dialysed until no trace of any crystalline substances which had formed during the germination could be detected in the dialysate. No trace of peptone passed the dialyser even after a week's exposure. The extract was then acidified with hydrochloric acid to the extent of 0-2 per cent., put into a fresh dialyser, some swollen-up boiled fibrin added, and the dialyser surrounded with 0-2 per cent. hydrochloric acid, and exposed to a temperature of 40°." Control experiments with acid only, or with boiled digestive extract, were carried out side by side. Digestion was slow, but after some time the dialysate contained peptone and leucine, while in the control experiments there were no such substances. The proteïds of the seeds are changed by this ferment in the same way as fibrin is. The ferment exists in the resting sced as a zymogen,

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