From this it appears that the increase of the total quantity of urine excreted is accompanied by diminished specific gravity, and that the excretion of extractives is increased both absolutely and proportionally to the total of nitrogenous substances in the urine; the total quantity of nitrogen from extractives in the group of seven days averaging 1.64 gram, and in the other group 2.14. A second series of observations was made to determine the influence of proteïd food on the output of both sources of nitrogen. The experiment was carried out on four persons, each of whom partook of one meat meal in the 24 hours, and whose urine was collected at intervals of three hours. Details similar to those enumerated in the previous experiments are tabulated, and the general results are the following:The increase in both kinds of nitrogen commences almost immediately after the digestion of the proteïd food; the nitrogen derived from urea reaches its maximum in from 7 to 10 hours, whilst that derived from the extractives is greatest in the four first hours after the commencement of the meal. The percentage difference is greatest during the first three hours and smallest 12 hours after the meal. The quantity of urine is smallest during the first four hours, and greatest from 7 to 10 hours after the meal; the most concentrated urine is thus accompanied by the secretion of the maximum of extractives, which is the opposite to the general result obtained from the first series of experiments.

From the large number of experiments performed, it is found that on the average for every 100 grams of nitrogen found by Hüfner's method, 136 must be added to obtain the total nitrogen; and this method of calculating the total nitrogen gives very good practical W. D. H.

results.

Cystin in Normal Urine. By E. GOLDMANN and E. BAUMANN (Zeit. physiol. Chem., 12, 254-261).-Stadthagen (Abstr., 1885, 830) has stated that normal urine contains no cystin, or only minimal quantities of that substance. In 12 experiments, the average amount of sulphur from cystin or allied substances was only 0.0003 gram per litre of urine.

It was thought necessary to repeat these observations, because investigations on the properties of pure cystin showed that Stadthagen's method was not calculated to yield accurate results.

If a few drops of benzoic chloride is added to a solution of pure cystin in sodium hydroxide, a voluminous precipitate of shining plates of the sodium salt of benzoylcystin, C.HoN2S2O4BZ2, is produced. This salt is soluble in hot, less soluble in cold water, and quite insoluble when excess of sodium hydroxide is present. By adding acid to this, benzoylcystin itself is obtained. It is a strong acid, insoluble in water, slightly soluble in pure ether, more so in a mixture of alcohol and ether, and still more so in alcohol. It crystallises in slender needles, melts at 156-158°, and is decomposed into benzoic acid and cystin by boiling with strong acids. By boiling with alkalis, it yields up its sulphur like cystin.

The circumstance that this compound is easily separated from watery fluids by means of ether, renders it easy to obtain cystin from the urine when it is present there. In some preliminary experiments known weights of benzoylcystin were mixed with urine, extracted therefrom by ether; the ethereal solution was evaporated to dryness, the residue taken up with sodium hydroxide, and the sulphur weighed as lead sulphide. The lead sulphide obtained, however, only corresponded to about two-thirds of the cystin used. On treating normal urine in this way, a precipitate of lead sulphide was always obtained, and the amount of sulphur was always greater than in Stadthagen's experiments, but as the cystin is not all decomposed, no exact quantitative statements can be made. The statement commonly made that cystin gives up its sulphur easily and completely on heating with alkalis is incorrect; after many hours' boiling, the cystin still retains a large percentage of sulphur, and this percentage is still greater in the presence of the other constituents of urine. It can, therefore, be said that cystin or a substance like cystin always occurs in urine, but no accurate quantitative statement can be made on the subject. The quantity was increased in dogs by poisoning with phosphorus. Perhaps different isomerides of cystin exist, which differ in the readiness with which they give up their sulphur. W. D. H.

Spontaneous Decomposition of Bilirubin. By E. SALKOWSKI (Zeit. physiol. Chem., 12, 227).—In two cases of strongly icteric urine it was noticed that after the occurrence of the ammoniacal fermentation, Gmelin's and Huppert's colour reactions were no longer given. Methods of extraction and precipitation, moreover, yielded no unchanged biliary pigment; dark, amorphous masses only were obtained. This decomposition of bilirubin without the production of any characteristic products, is probably the result of the activity of bacteria, and may probably explain other cases of jaundice in which the urine, though darkly coloured, gave no evidence of bile pigment.

W. D. H. Poisonous Properties of Dinitrocresol. By T. WEYL (Ber., 21, 512; compare this vol., p. 184).-Doses of 0.054 gram per kilo. bodyweight, suspended in a little water or milk, introduced into the stomachs of dogs (of 5 to 7 kilos.), caused in a few minutes great

difficulty in breathing, and convulsions, during which the animals die. Doses of 0.02 gram per kilo. body-weight, dissolved in aqueous alcohol, and applied subcutaneously to moderate-sized dogs, brought on the same symptoms and death in 1 to 1 hours. Some animals recovered after 3 to 4 hours. N. H. M.

Chemistry of Vegetable Physiology and Agriculture.

Nitrification of Ammonia and its Salts. By H. PLATH (Bied. Centr., 1888, 6-8).—Frank was led to the conclusion that, although certain species of bacteria may be able to help nitrification in the soil, yet in general the action is produced without the intervention of organisms; he isolated various forms of fungi from the soil, and found that they possessed no power of nitrifying ammonia, also that sterilised soil nitrified ammonium chloride about as quickly as the original soil, and he concluded from some experiments that the calcium carbonate of the soil in presence of water and air produces a slow combination of the nitrogen to nitrous and nitric acids. Dumas (1846) found that by passing moist air and ammonia at about 100°, over chalk for some days, a noticeable quantity of potassium nitrate is formed. Later communications state that this happens also at ordinary temperatures. Millon (1860) asserted that humus had a direct action in nitrifying ammonia.

The author's work aimed at a repetition of that of the above experimenters, and he came to the conclusion that when the action of organisms is eliminated by sterilising soil, neither its individual constituents singly, nor the soil as a whole, can nitrify ammonia, and that, further, the nitrifying power must be due to micro-organisms, and, lastly, that the power of oxidising atmospheric nitrogen cannot be ascribed to calcium carbonate. Frank has since protested against Plath's conclusions, objecting that some important experiments of his were not repeated, and that in order to prove that organisms are the nitrifying agents, Plath has yet to show that the heat employed in sterilising produced no change in the soil other than the death of the organisms. H. H. R.

Aspidium Felix, Mas. L. By G. DACCOмO (Chem. Centr., 1887, 1357-1358; from Ann. Chim. Farm., 87, 69—90).—If the ether extract residue of the rootstock of aspidium (male fern) is treated with 2 vols. of 95 per cent. alcohol and 1 vol. of ether, a brown residue is left which is partially soluble in 1 per cent. aqueous potash. The soluble portion is the filicin or filicic acid of Trommsdorf; the insoluble part separates from an alcoholic solution as a white, floccular, waxy substance, (C13H2O)n, melting at 80°, it is insoluble in water, sparingly soluble in ether and cold alcohol, but soluble in hot alcohol; it is not decomposed by boiling alcoholic

potash, and gives no coloration with sulphuric acid and chloro

form.

The residue obtained by evaporating the alcohol-ether solution of the original extract, when extracted with water, furnishes glucose and tannin, and with 95 per cent. alcohol a black resin which is almost completely soluble in 2 per cent. aqueous potash. The residue of the extract, insoluble both in water and alcohol, is a green oil difficult to saponify.

The blood-red alkaline solution when agitated with ether parts with some of the red colouring matter (felix red). The residue of this ether extract when distilled with steam furnishes the essential oil of felix; this essential oil appears not to pre-exist in the plant. The residue from this distillation, when extracted with ether, gives, when the ether is evaporated, a red liquid and a precipitate, which, after crystallising from hot alcohol, forms plates melting at 136.5°, having the composition C20H3O. This compound has received the name of aspidol. It is insoluble in alkalis, easily soluble in ether, benzene, chloroform, light petroleum, and hot alcohol. It is optically active in a 3 per cent. chloroform solution [a]D =-24.08. The filtrate from this precipitate of aspidol was fractionated into three parts. The first fraction, 130-190°, was a yellow oil with a strong odour and acid reaction, which did not reduce silver nitrate. The second fraction, 220-290°, was a beautiful green oil, which gradually became brown; it has the empirical formula (C2H6O2). The third fraction above 300° (at 200 mm. pressure) corresponds with the formula (CsHO,).

58

By precipitating the alkaline solution extracted with ether with sulphuric acid, two resins were obtained: 1st, a brick-red solid melting at 85-93°; 2nd, a more abundant and almost black, plastic The filtrate contains butyric acid.

mass.

J. P. L.

Ensilage Processes. By A. CSERHÁTI (Bied. Centr., 1888, 39-43). -The value of an ensilage process is determined chiefly by the loss of substance, and by the quantity and nature of the acids produced; the two first items should be as small as possible. The author experimented with various fodders ensiled in glass cylinders or in boxes sunk in the ground. On comparing the merits of fresh fodder with wilted fodder for making silage, be found that the temperature rose slightly higher, and that the loss of substance was greater in the case of the wilted fodder. On comparing the effect of stamping the fodder well down in the silo with only stamping it down round the edges, he found that the temperature rose considerably higher in the latter case. Fry's method of allowing the material to heat and rise to 50° in order to stop the development of micro-organisms, and so to diminish the amount of acid formed is most expensive in loss of material. To see whether such a high temperature was necessary, the author tried stamping the fodders well down, and keeping the temperature under 30° as far as possible. He found that although the amount of acid in the silage was higher than that given by Fry, yet it was in itself very small. He concludes that by proper precautions, namely: having perpendicular walls for the silo; using

fresh fodder; thorough stamping; having a level covering, and heavy weighting, the amount of acid can be kept down without incurring the loss that the employment of Fry's method involves.

H. H. R.

Ensilage in the Open Air. By M. BARTH (Bied. Centr., 1888, 64). -A description of the way a stack of silage was made, and of the composition of the resulting silage. H. H. R.

Exhaustion of Virgin Soils in Australasia. By R. W. E. MACIVOR (Chem. News, 57, 25-26).-The exhaustion of the virgin soils of Australasia is in great part due to the bad system of cultivation giving rise to waste of nitrogen. To grow wheat continuously, the ground is ploughed year after year to a depth of 2 to 3 inches, thus giving a very shallow surface soil, whilst the continual passage of the shoe of the plough converts the subsoil into a firm compact bed almost impenetrable by the roots of wheat. The surface soil soon becomes dry, and oxidises readily with loss of humus and nitrogen. Another source of loss is the burning the straw. The deficiency of nitrogen is least observed in heavy soils derived from rocks of volcanic origin, then follow those soils traceable to silurian and primitive rocks, whilst light friable soils when in dry and exposed districts are the poorest soils and the greatest sufferers. Soils in New Zealand, Tasmania, and the cooler parts of Australia, contain more nitrogen than soils of the same formation in drier and hotter localities. Dressings of non-nitrogenous manures proved quite useless, and even nitrogenous manures yielded an increased crop without profit. An occasional bare fallow restores matters for a time, but ultimately even that does no good. The introduction of a leguminous crop from time to time has proved beneficial. D. A. L.

Maintenance and Increase of the Amount of Combined Nitrogen on the Farm. By J. KÖNIG (Bied. Centr., 1888, 16—31). -The first part of this article treats of the natural sources of nitrogen to plants, and discusses the work of previous experimenters bearing on the question; then Hellriegel's investigations are described. He found that the Graminacea are dependent for their nitrogen on the combined nitrogen of the soil, and that most probably they only avail themselves of it when it has been transformed into nitrates. In the case of the Papilionacea it is quite different. When peas were grown in a soil containing no nitrogen, they first used that which was stored in the seed; when this had all been employed, there was for a time an evident halt in their growth which, however, was only temporary, and they eventually succeeded in supplying themselves with nitrogen from some other source. Their subsequent development varied mach in different experiments, although the conditions of growth were the To discover whether these variations could be due to the combined nitrogen of the air, one set of plants were grown in ordinary air and another set in air freed from ammonia and nitric acid; the results showed that this was not the cause of the variation, and led to the conclusion that the free nitrogen of the air must somehow become available to the peas. An examination of the roots showed

same.