Page images
PDF
EPUB

the vasomotor centres being paralysed. No direct effect is produced on the heart. The temperature is reduced considerably. Trimethyl carbinol acts in the same way, but less powerfully. The author deduces from his experiments that whilst primary alcohols have a generally stimulating action, tertiary alcohols, even though isomeric with them, act as depressants.

T. M.

Myoctonine. By G. DRAGENDORFF and S. SALOMONOWITSCH (Chem. Centr., 1886, 861).-This alkaloïd occurs, together with lycaconitine (Chem. Centr., 1884, 29) in Aconitus lycoctonum; it differs from the latter in melting point (144°) and solubilities. It is freely soluble in chloroform, nearly insoluble in ether. Lycaconitine being on the other hand soluble in ether, the separation of the alkaloïds is effected by means of this menstruum. The physiological action of the alkaloids is closely similar. The lethal dose of the myoctonine, in the case of frogs, is 001 gram; characteristic symptoms of its action are obtainable with 0.00003 gram. These are, in the main, paralysis of the extremities of the motor nerves, the medulla and nerve trunks remaining unaffected, as also the muscular irritability. The injection of 0.025 gram of the nitrate into the vena jugulari of cats caused instantaneous death; the subcutaneous injection of 01 gram caused death within 20 to 30 minutes. Twice this quantity introduced per os caused similar results.

For the isolation of myoctonine from animal fluids, the authors recommend shaking with benzene, after the usual preliminary purification, and rendering alkaline with ammonia. After death caused by subcutaneous injection, the alkaloïd is found in the coats, but not the contents, of the stomach and intestines; in the blood, liver, and kidneys in relatively large quantity; in small quantity in the pancreas. C. F. C.

Chemistry of Vegetable Physiology and Agriculture.

Nitrification. By A. CELLI and F. MARINO-Zuco (Gazzetta, 17, 99-103). In the course of analyses of water from the subsoil of Rome, amongst other organisms a micrococcus of globular form (Micrococcus cereus) was discovered; this was found to be a very effica cious nitrifying agent.

Preliminary experiments are quoted to prove that for the process of nitrification the presence of bacteria is not absolutely essential, for if sterilised solutions of ammonium salt are filtered through sterilised sand or platinum sponge, nitrification ensues to an appreciable degree. It is further shown that among the organisms which liquefy nutritive gelatin Bacillus saprogenus, B. fluidificans, and Micrococcus luteus, when thrown on to sand in cultivating liquids, not only do not produce nitrates but destroy them completely; on the other hand these same

organisms, taken from potato-cultures, far from destroying the nitrates, are among the most active agents in producing them.

V. H. V.

Action of Alkaloïds in the Animal and Vegetable Kingdom. By A. MARCACCI (Chem. Centr., 1887, 248).—Fermentation of milk was promoted by addition of water, potassium and sodium sulphate, sodium chloride, atropine and morphine sulphate, but impeded by veratrine sulphate, quinine hydrochloride, cinchonamine sulphate, and especially by strychnine sulphate. Solutions of the above salts, with the exception of those of cinchonamine and quinine, as compared with the water, promote alcoholic fermentation. In order to study the action of alkaloïds on seeds, the latter were either soaked in the solutions and then planted out, or allowed to sprout and grow in powdered glass, and then watered with the solution. The sprouting process was hardly influenced by salts of morphine, but affected by those of strychnine, veratrine, and especially of quinine and cinchonamine. The alkaloïd salts have a most injurious effect on maize, beans, and lupines. On already developed plants, morphine salts produce no effect, but salts of strychnine, and especially quinine and cinchonamine, are very detrimental. Strychnine hinders the development of frog spawn, but morphine and atropine favour it as compared with distilled water. Tadpoles are quickly killed in solutions of salts of veratrine, strychnine, and quinine, but more slowly in atropine and distilled water; whilst frogs are more quickly killed by strychnine and veratrine, but will live for several months in a solution of morphine. As regards the effect of poison, there appears to be no marked difference between animal and plant protoplasm, nor a definite classification into animal and plant poisons. V. H. V.

Are Nitrates formed in the Organism of Higher Plants ? By E. SCHULZE (Ber., 20, 1500-1504).-Lupin sprouts grown on paraffined gauze stretched over flat vessels filled with distilled water, were found to be free from nitrates. On the other hand, when the lupin sprouts were grown in a moist sand, they were found to contain nitrates. It is shown that nitrogenous substance is taken up by the water, and that this is partially converted into nitrates in presence of sand. The author does not insist that the nitrates found in the sprouts grown in sand can only have been formed from nitrogenous substance separated from the roots, but maintains that the presence of nitrates is no proof of Berthelot and André's view, that nitrates are formed in the organism of higher plants (compare also this vol., p. 686). N. H. M.

Carrotene in Leaves. By A. ARNAUD (Compt. rend., 104, 1293— 1296). Carrotene (Abstr., 1886, 711) is always found in the leaves of plants in full vegetation.

Leaves dried in a dry vacuum contain the whole of the original carrotene, but this is not the case if they are dried by heat. Light petroleum boiling below 100°, and free from benzene, dissolves carrotene, but not chlorophyll. Carrotene dissolves in almost any

proportion in carbon bisulphide, forming a solution with an intense blood-red colour.

A known weight (20 grams) of the leaves dried in a vacuum, is treated with a definite volume (1000 c.c.) of light petroleum boiling below 100°, and is allowed to remain at the ordinary temperature for 10 days, with occasional shaking. A definite fraction (100 c.c.) is placed in a dish, allowed to evaporate to dryness, and the residue dissolved in carbon bisulphide so that the solution measures 100 c.c., which will correspond with one-tenth of the total carrotene present in the weight of leaves taken. The intensity of the colour of the solution is measured by means of a Duboscq colorimeter, and is compared with a solution of pure carrotene of known strength.

The amount of carrotene is equal on an average to about 0.1 per cent. of the weight of the dried leaves, and it must exert a considerable influence on the colour of the leaves. C. H. B.

Organic and Inorganic Constituents of Grapes. By E. LIST (Chem. Centr., 1887, 245-246).-The author has made an investigation into the organic and inorganic constituents of grapes of the Franconia district, as influenced by the nature of the soil and the manure applied, and examined the action of various ferments on the pressed juice. Results are given of (i) the composition of 39 various species; (ii) the proportion of mineral matter present in the juice; (iii) the percentage composition of the ash; and (iv) the composition of the fermented juice. From the results it follows (i) that the proportion of each constituent varies within wider limits than hitherto supposed; (ii) the ratio 100: 7 of alcohol to glycerol as a minimum is not absolute; and (iii) the ferments abstract from the juice a considerable quantity of phosphates, but these are again returned after some time to the wine on the breaking down of the ferment-cells. V. H. V.

Solanine. By G. KASSNER (Arch. Pharm. [3], 25, 402-403).— Siftings from diseased potatoes gave as much as 0·03-0·05 gram of solanine from 120 grams, whilst sound potatoes of the same kind gave scarcely any. The observations were made in January, showing that solanine may be formed in potatoes during the period of winter rest. J. T.

Tunisian Soils. By H. QUANTIN (Compt. rend., 104, 1528-1529). -A series of determinations of nitrogen and phosphoric acid in soils in various parts of Tunis. In the valley of the Medjerdah the soils show a deficiency in phosphoric acid, a result which is due to the growth of cereals from time immemorial without any restitution of phosphates being made. This is the cause of the mediocre crops which are now obtained, and the deposits of phosphates recently found by Thomas in Tunis will be of very great value as a means of restoring fertility to the exhausted soils. C. H. B.

Evolution of Ammonia from Vegetable Soils. By BERTHELOT and ANDRÉ (Compt. rend., 104, 1219-1224).-The soil, which had undergone no previous treatment, was placed in a flask and subjected to a current of air, which was afterwards passed through cotton-wool

and then through bulbs containing dilute standard sulphuric acid. In other cases the soil was placed under a bell-jar, together with a dish containing the acid.

Vegetable soils evolve ammonia spontaneously, in consequence of the slow decomposition of the ammoniacal and amidated compounds present in the soil. This decomposition is partly due to the chemical action of the water, carbonates, &c., and partly to physiological actions such as fermentation, the development and activity of microbes, and vegetation proper. Most of the reactions concerned in the evolution of the ammonia are non-reversible.

A comparison between the amount of ammonia evolved from the soil, and the amount present in the atmosphere, and therefore capable of being absorbed by the soil, was made by supporting a flat dish containing sulphuric acid just above the top of the grass in a grassfield, the dish being protected at night and during rain and the loss by evaporation being compensated by addition of water. dish was supported inside an earthenware cylinder which isolated a portion of the soil and grass from the surrounding soil. Care was taken that the duration of the experiment was not sufficiently long for the grass enclosed in the cylinder to become etiolated. The sulphuric acid was not titrated, but was made alkaline and distilled.

The amount of ammonia existing in the air is extremely variable, and changes with every change in meteorological conditions. The evolution of ammonia from the soil is much more regular; it is in fact conditioned by comparatively regular natural processes. In all cases there is no necessary connection between the tension of the ammonia in the atmosphere and the evolution of this gas from the soil. The two phenomena, the absorption of ammonia by the soil from the air and the evolution of ammonia from the soil into the air, are independent of one another. C. H. B.

Agricultural Value of Retrograde Phosphate. By J. Joffre (Bull. Soc. Chim., 47, 812-316).-The coefficient of solubility of ferric phosphate, known as retrograde phosphate, in water is about 0.000002, and therefore differs but little from that of raw, or tricalcium phosphate. Experiments conducted on crops show that the use of tricalcium phosphate has a slight advantage over the retrograde phosphate. The following results were obtained, 22.5 kilos. of combined phosphoric acid being applied per hectare in the form of the different manures:

Without any phosphatic manure = 1441 kilos. of grain per hectare.
With retrograde phosphate ..... = 1.559
With insoluble phosphatic nodules = 1.580
With soluble phosphate

[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]

= 1·736

[ocr errors]
[ocr errors]

A. P.

Analytical Chemistry.

Estimation of Hydrogen Peroxide. By H. THOMAS (Chem. Centr., 1887, 283).-The amount of hydrogen peroxide in a solution is estimated by acidifying with sulphuric acid, adding a solution of potassium iodide free from iodate, and determining the iodine liberated by means of a standard solution of sodium thiosulphate.

V. H. V.

Volumetric Estimation of Iodine. By T. SALZER (Chem. Zeit., 11, 754). The degree of dilution of the sodium sulphite solution used in estimating iodine by Kalmann's process materially influences the result. With a constant degree of dilution, however, the author states that the results agree very well amongst themselves.

J. P. L.

Determination of Sulphuric Acid in Water. By FRICKE (Chem. Centr., 1887, 283).-As various methods suggested for the determination of sulphuric acid in samples of water are far from accurate, the following process is proposed; 200 c.c. of the water is boiled with a few drops of a solution of sodium carbonate to precipitate the lime. The volume is again made up and 100 c.c. withdrawn by a pipette, neutralised, and boiled with baryta-water of known concentration; the excess of the baryta is precipitated by carbonic anhydride, and the whole boiled. The precipitate of sulphate and carbonate is filtered off, and the latter decomposed by a decinormal solution of hydrochloric acid. From the quantity of the solution used the excess of the barium hydrate is calculated, and deducting this, the amount of the hydrate required to precipitate the sulphuric acid is calculated. The formation of a soluble acid barium carbonate not decomposed by boiling on passing in the carbonic anhydride, is a source of error too small to be appreciable. V. H. V.

Estimation of Nitrogen in Organic Substances. By RAULIN (Bull. Soc. Chim., 47, 94-97).-A modification of Dumas' process. The tube in which the combustion is conducted is of copper, about 3 mm. thick, and having an internal diameter of 18 mm. The length of the tube is 1800 mm., and arranged along it at equal distances are four small brass water-jackets, each about 100 mm. in length, one of which is placed at either end, and the other two at equal distances between, thus dividing the outside surface of the copper tube into three portions of about 500 mm. each. In each of these uncovered portions of the tube a separate combustion is conducted; the space nearest the front is first charged by introducing a coil of sheet copper about 60 mm. long; with the aid of a glass funnel 60 grams of small fragments of copper oxide are then added, and finally a convenient weight of the organic compound mixed with a small quantity of fine copper oxide and about 20 grams of coarser fragments; the funnel and back part of the tube are then rinsed down with a small quantity of copper oxide, and a second and third charge

« PreviousContinue »