386

ELEMENTS OB' MATERIA MED1CA.

3. An Acid {Lobelie ? aeid). —A decoction of lobelia reddens litmus, and becomes, on theaddition of sesquichloride of iron, dark, olive brown ; and in a short time a preeipitate is formed(lobeliale ? of iron). A Solution of isinglass produced no obvious change in the decoction,showing the absence of tannio acid. Sulpnate of eopper give rise to a green preeipitate (lobe.liate? of eopper). Nitrate of silver eaused a slight preeipitate (lobeliale ? of silver) soloble innitric acid. The effeet produced by the saits of iron on decoction of lobelia is analogous lothat eaused by the sarnc agents on aloes (see p. 110), and cebadilla (see p. 99). [Lobelie aeidmay be obtained by vvashing the preeipitate resuking from the addition of sulphate of eopperto a concentrated decoction of lobelia, until it ceased to affect litmus, afterwards suspending itin water and preeipitating the eopper by a current of hydrosulphurie acid. The liquor by fil-tration and evaporation yields the impure acid, which by treatment with ether and evaporationjs obtained in a yellow semi-crystalline mass. It is not preeipitated by ehloride of barium(Procter).]

4. Resin. —By gently evaporating the lineture of Jobelia (prepared with proof spirit) a resin-ous substanee separates and floats on the surface of the liquid. It has an exceedingly aeridtaste.

[5. Fixeu On..—The sceds of lobelia eontain 30 per cent. of a limpid fixed oil; sp. gr. - 940,and posesssing the properties of a drying oil (Procter).]

Chemical Characteristics. —A strong decoction of lobelia dropped intorectified spirit deposits a preeipitate {ßum). Acetate, and especially diacetateof lead, form yellow preeipitates with the decoction. Protonitrate of mercuryalso forms a copious preeipitate. (For other chemical characteristics, see above.)

Physiological Effects. —An aecurate aecount of the effects of this plant onman and animals is yet wanting. But from the observations hitherto made itsOperation appears to be very similar to that of töbacco (see p. 317); and fromthis circumstance, indeed, it has been called the Indian Tobacco. I have beforeremarked, that both in its taste and in the Sensation of acridity which it excitesin the throat, it resembles common tobaeco. This analogy between nicotianaand lobelia, originally noticed by the American practitioners, is confirmed byDr. Elliotson. (Lancet, April 15, 1837, p. 144.)

a. On Animals generatty. —Horses and cattle have been supposed to be killedby eating it accidentally. (Thacher, American New Dispensatory, p. 2.) Anextraordinary flow of saliva is said to be produced by it on cattle. (Lancet, May13, 1837, p. 299.)

[Mr. Procter administered a grain of lobelina in Solution to a cat. In less thantwo rainutes it produced violenf emesis, and much prostration, from which thoanimal fully recovered in three hours. Again, one grain of the substance in anbunce of water was administered directly into the stomach of the animal by anelastic tube. lmmediate and total prostration was the consequence, which inhalf an hour rendered the animal almost motionless ; the pupils of the eyes weremuch dilated. The animal gradually recovered its strength, but the effects ofthe prostration were evident for nfteen hours afterwards. No emetic or catharticeffects resulted. {Am. Journ. of Pharm, vol. xiii. p. 10.)—J. C]

ß. On Man. —aa. In small doses it operates as a diapkoretic and expecto-rant. Mr. Andrews, {Land. Med. Gaz. vol. iii. p. 260,) who speaks from itseffects on himself, says, it has " the pecular soothing quality of exciting expec-toration without the pain of coughing."

ßß. Infuttmedicinal doses (as Bj. of the powder) it acts as a powerful, nau-seating emetic. Hence it has been called the emetic iveed. It causes severeand speedy vomiting, attended with continued and distressing nausea, sometimespurging, copious sweating, and great general relaxation. These Symptoms areusuaüy preceded by giddiness, headache, and general tremors. The Rev. Dr.M. Cutler, (Thacher, op. cit.,) in his aecount of the effects on himself, says, thattaken during a severe paroxysm of asthma, it eaused sickness and vomiting, anda kind of prickly Sensation through the whole system, even to the extremities oftho fingers and toes. The urinary passage was perceptibly affected, by produc-ing a smarting Sensation in passing urine, which was probably provoked by Sti-mulus on the bladder. It sometimes, as in the Rev. Dr. Cutler's casc, givesalmost instantaneoim relief in an attack of spasmodic asthma. Intermittentpulse was eaused by it in a case mentioned by Dr. Elliotson. Administered by