[ 599 ] PART III. MEDICAL INTELLIGENCE. CHEMISTRY. Liquidhation and Solidification of Carbonic Acid Gas.?It is well known that it has long been an important problem in practical Chemistry, to re- duce to the liquid and solid form those gaseous bodies, which, being hither- to only known in the gaseous shape, have been very generally denominat- ed by chemists permanently elasticJluids. This denomination, there is now reason to presume, from the advanced progress of chemistry, and the in- creased power of its resources, will be no longer justly applicable. It is known, at least, that chemists have lately succeeded in liquefying carbonic acid gas, or causing it to assume the form of a liquid, chiefly by means of very great pressure. Mr Faraday, in this country, made the gas assume a liquid form, by subjecting it, within a strong glass tube, to the pressure of 36 atmospheres at 32? of Fahrenheit's thermometer; and M. Thilorier of Paris produced in 1835 the same result in a similar manner. (Annalesde Chimie et de Physique, Tom. lx. p. 427 and 432. Paris 1835.) In this state, if allowed to escape, it immediately evaporates, and a most intense degree of cold, estimated at?180?, is produced, while part of the carbonic acid is converted into the solid form, in the shape of small whitish woolly flocks or masses, which are intensely cold, and which adhere so strongly to the walls of the glass, that it is impossible to get it out by any other method than breaking the flask. This is the solidified gas ; in other words, a substance supposed to be permanently elastic and gaseous, con- verted into a solid. On Wednesday, the 14th February 1838, this interesting experiment was performed in the chemical class-room of the University, in the pre- sence of the Fellows of the Royal Society, the Fellows of the Royal Colleges of Physicians and Surgeons, and several literary and scientific gentlemen. Mr Kemp, practical assistant to Dr Hope, Professor of Chemistry in the University, had, by the combined effects of high pressure and intense cold, reduced carbonic acid to the liquidized form with a degree of facility, which enables him to present it in considerable quantity, and perform with it se- veral striking and interesting experiments. His method is to confine the gas thus liquidized in a very strong cylindrical vessel of copper, which is provided with a stop-cock, from which the liquefied gas is allowed to escape in the quantities, and at the rate which the experimenter deems pro- per. To one side of this vessel, also, is attached a glass tube, communi- cating with the interior of the copper cylinder, and in which the liquefi- ed carbonic acid gas may be seen. Dr Hope first allowed a quantity of the liquefied gas to escape by turn- ing slightly the stop-cock, when it rushed out with a peculiar hissing sound, and was received in an ordinary glass flask. As it issued, part eva- porated, and at the same time was formed in the glass flask a quantity of white friable solid matter, which fell to the bottom of the vessel, and could be heard striking against the interior as it was shaken or moved. This substance is intensely cold, and the degree of cold produced is so great, that it is impossible to touch the glass with the uncovered hand. The flask was, after a sufficient quantity had been received, broken, and a mass of solidified carbonic acid gas, as large as a filbert, was then presented to view. 600 On the Grains of TeeJ. The theory of the solidification in this case, Dr Hope explained, was, that, while part of the liquidized gas is evaporated, the moment the weighty pressure is withdrawn, the cold produced is so intense, as to reduce from the liquid to the solid form the residual part. Thus incessantly as a jet of li- quidized gas continues to escape, part is evaporated, and the cold thus pro- duced is sufficient to freeze the rest. The next experiment was a very conclusive one. It is well known that mercury requires for its congelation a temperature of?40?, that is 40? be- low zero of Fahrenheit. A quantity of the liquidized gas was allowed to issue from the copper cylinder, and received into a glass flask, in which was introduced a quantity of liquid mercury. In the space of two minutes it was frozen into a solid mass, which could be divided with the knife. A portion of this mercury dropped into a glass of water gradually but rapidly fell down in its usual fluid form, while in its place was left a mass of ice of exactly the same shape and size. This shows that the cold capable of being produced by the solidification of carbonic acid gas must be very great. MATERIA MEDICA. On the grains of Teel or Till or Ramtilla, Nook in Abyssynia, Verinnua or Kutrello in I/idostan, and the edible oil obtained from it. (Journal de Pharmacie, No. vii. 23d annee, July 1837.)?Of this oleaginous seed, which, on account of the abundant oil so easily obtained, is very well cultivated in all hot countries, eleven hundred bags have been recently imported from Calcutta into France. This very minute grain, akene of botanists, consists of a quadrangular oval bursa opening at the base with four valves, which has caused it to be arranged by some authors with the genus Tetragonotheca. Its colour is tawny or brown ; it is remarkable neither for smell nor taste ; and it fur- nishes little mucilage but an astringent principle. It is sufficient to crush and squeeze forcibly these seeds, with or without the aid of heat, to obtain a limpid oil, which has nothing disagreeable in taste, and which may be used at table, without, however, surpassing that of the poppy seeds or se- same seeds. It was formerly said, (Journal de Pharmacie, Tome xxi. p. 105.) that the Ramtilla of the East Indies and Abyssinia belonged to the family of the Compositw. It approaches the Senecios, and resembles our marigolds, with little yellow flowers. Its grains, placed in the centre of the floral disc, are void of tufts. As it can live only under tropical skies, the plant is not susceptible of cultivation in Europe. Meanwhile, as it is an annual, it might be practicable to propagate it in certain localities, well exposed, and sheltered from the cold, in the southern countries, on account of its great utility. The following is a list of the botanical names by which this plant has been designated in the systems of different botanists. In 1781, the younger Linne called it a Polymnia Abyssinica, after the Polymniafrondosa of Bruce, (Travels to discover the Source of the Nile, 4to. Vol. iii. p. 575.) or Nook of the Abyssinians, by whom it is cultivated. It is the Verbesina saliva of Roxburgh, Catalogue, p. 62, and of Sims, (Botanical Magazine, pi. 1017,) and of Ainslie, (Materia Indiea, Vol. ii. p. 256.) Verinnua of Heyne, Tract on Ind Plants, p. 49. Parfhenium luteum of Sprengel, Nov. Prod. 1818, p. 31. Jaegera Abyssinica of Sprengel, Systema Plant. 1826, p. 590. Heliopsis platyglossa of Cassini, Diet. Botanique, p. 332. Guizotia Abyssinica, Cassini, Diet. Botanique, (1829) p. 248. Tetragonotheca Abyssinica of Ledeboer, Index horti Dorpatensis, supple- ment, 1824, p. 7. Helianthus oleifer of Wallich, Catal. et hcrbas., No. 319, Bidens ? Ham- tilia of Wallich, No. 3191, comp. 301. Anthemis Mysorensis of Wallich in his Herbarium of Madras. Diuretic operation of the Aralia liispida. 601 Ramtilla oleifera, Decandolle, Mem. de la Societe de Geneve, 1833, and in Contributions to Indian Botany by Wight, p. 18. Guizotia oleifera, Decandolle, Prodromus Systematis Regni Vegetabilis, Tom. v. 1836, p. 551. Buphthalmum Ramtilla of Hamilton, Herbarium. Of this plant two varieties are known. The cultivated variety (sativa) has leaves larger, well-grown leaves, elongated, lanceolate, broadly denti- culate, with foot-stalks in corymbiferous branches. Of the wild variety, (angustior,) the leaves are almost linear, and the branches are axillary, floriferous, and very short. Diuretic operation pfthe Aralia hispida. By Doctor Oliver Peck.?The Aralia hispida grows very abundantly in the country of Massachusetts, and has for several years been employed by physicians as a diuretic. It is there called hycbla, on account of its resemblance to the Samhucus Cana- densis, although it is a much smaller plant. It grows in cultivated lands which have been neglected, and scarcely attains the height of a foot and a half. Its stem is tufted at the base, and covered with hard spines; its leaves are sessile, deeply denticulated, about one inch long; the footstalks terminal and axillary, bearing from two to four umbels ; the flower of a greenish white, with reflected petals ; and the root of a sweetish taste. It is the root that is preferably employed, and in decoction it is taken ad libitum. To the advantages of an energetic diuretic operation, it unites that of being agreeable in taste, and more easily endured by the stomach, than all the other remedies of the same kind. The author relates a case in which the administration of this plant in a woman labouring under diseased heart, produced more relief with much less inconvenience than a great many other diuretics. But no details illustrative of its physiological operation and effects are communicated. Properties of the Ceanothus Americavus. By Dr Hubbard.?This plant, which grows very abundantly on the dry sandy flats of America, ap- pears to possess very powerful astringent properties. It is described in the following manner by Professor Bigelow.