portion of the aqueous solution until the fluid acquires a scarcely perceptible alkaline reaction; stir, and let the fluid stand for some

time.

a. No PRECIPITATE IS FORMED; this proves the total absence of the alkaloids, and indicates the presence of SALICINE. To set all doubt at rest, test the original substance with concentrated sulphuric acid, and also with hydrochloric acid. Compare § 244. b. A PRECIPITATE IS FORMED. Add solution of potassa or soda, drop by drop, until the fluid manifests a strongly alkaline reaction.

a. The precipitate redissolves: MORPHIA. To arrive at a positive conclusion on this point, test another portion of the solution with iodic acid (§ 235, 9), and a portion of the ori ginal substance with sulphuric acid, &c., (§ 235, 7).

In this method, which is more especially applicable in cases where the disposable quantity of substance is very small, the alkaloids are supposed to be present in the pure state and in the solid form.

1. Treat the substance under examination with from 4 to 6 drops of pure concen. trated sulphuric acid.

Yellow color, speedily changing to red: VERATRIA.

Rose color, changing afterwards to BRUCIA.

The other alkaloids, if pure, impart no color to the sulphuric acid.

2. No matter whether there is color or not; add to the fluid obtained in 1, from 8

to 20 drops of concentrated sulphuric acid mixed with nitric acid (see Toot-note to

§ 235, 7). then two or three drops of water. After a quarter or half-hour the £uid shows:

a. a violet-red color: MCRPHIA;

b. an onion-red color: NARCOTINA;

c. a transient red tint, changing to yellow: BRUCIA;

d. the red color of the sulphuric acid solution of VERATRIA is not materially altered;

e. with STRYCUNIA no coloration is observed.

3. Put into the fluid obtained in 2, no matter whether colored or not. from 4 to 6 clean fragments of binoxide of manganese, of the size of a lentil. After an hour the fluid shows;

a. a mahogany-brown color: MORPHIA;

b. a yellowish-red to blood-red color: NARCOTINA;

c. a transient purple-violet tint, changing to deep onion-red: STRYCHNIA;

d. a transient red tint, changing to gamboge-yellow: BRUCIA;

e. a dark dirty cherry-red color: VERATRIA;

4. Pour the colored fluid obtained in 3, into a test tube containing 4 times the volume of water, and add ammonia until the neutralization point is almost attained. Heat must be as much as possible avoided in these operations.

a. dirty-yellow color, changing to brownish-red upon supersaturation with ammonia, without immediate deposition of a notable precipitate: MORPHIA;

b. reddish coloration, more or less intense according to the degree of dilution; upon supersaturation with ammonia, copious dark-brown precipitate: NARCOTINA;

c. violet-purple colored solution, becoming yellowish-green to yell w upon addition of ammonia in excess: STRYCHNIA;

d. gold-yellow solution, not materially changed by excess of ammonia: BRUCIA; e. faint brownish solution, turning yellowish upon further addition of ammonia, and depositing a greenish light-brown precipitate: VERATRIA,

B. The precipitate remains undissolved: Presence of an alkaloid of the second or third group. Pass on to 2.

2. Add to a second portion of the original solution two or three drops of dilute sulphuric acid, then a saturated solution of bicar bonate of soda until the acid reaction is just neutralized; vigorously rub the inside of the vessel, and allow the mixture to stand for half an hour.

a. No PRECIPITATE IS PRODUCED: Absence of narcotina and cinchonia. Pass on to 3.

b. A PRECIPITATE IS FORMED: Narcotina, cinchonia, and perhaps also quina, as the precipitation of the latter substance by bicarbonate of soda depends entirely upon the degree of dilution of the fluid. Add to a portion of the original solution ammonia in excess, then a sufficient quantity of ether, and shake the mixture.

a. The precipitate which forms at first upon the addition of the ammonia redissolves in the ether, and the clear fluid presents two distinct layers: narcotina or quina. To distinguish between the two, test a fresh portion of the original solution with chlorine water and ammonia. If the solution turns green, QUINA, if yellowish-red, NARCOTINE is present. The reaction with a mixture of sulphuric acid and nitric acid (§ 286, 5) is resorted to as a conclusive test.

3. The precipitate which forms upon the addition of ammonia does not redissolve in the ether-CINCHONIA. The deportment of cinchonia at a high temperature (§ 238, 3), or the reaction with ferricyanide of potassium (§ 238, 8), may serve as a conclusive test.

3. Put a portion of the original substance, or of the residue remaining upon the evaporation of the solution, on a watch-glass, and treat with concentrated sulphuric acid.

a. A rose-coloured solution is obtained, which becomes intensely red upon addition of nitric acid: BRUCIA. The reaction with nitric acid and protochloride of tin is resorted to as a conclusive test (§ 241, 6).

b. A yellow solution is obtained, the color of which gradually changes to yellowish-red, then to blood-red, and turns finally crim.

son: VERATRIA.

c. A colorless fluid is obtained, which remains colorless after standing for some time.

Add to the fluid a fragment of chromate of potassa; if this imparts to it a deep blue color, STRYCHNIA is present; if it leaves the fluid unaltered, QUINA is present. The reaction with chlorine water and ammonia is resorted to as a conclusive test.

II. DETECTION OF THE ALKALOIDS, AND OF SALICINE, IN SOLUTIONS SUPPOSED TO CONTAIN SEVERAL OR ALL OF THESE SUBSTANCES. § 246.

1. Add to a portion of the aqueous solution dilute solution of potassa or soda, drop by drop, until the fluid acquires a scarcely perceptible alkaline reaction; stir, and let the fluid stand for some time.

a. NO PRECIPITATE IS FORMED; this proves the total absence of the alkaloids, and indicates the presence of SALICINE. To remove all doubt on the point, test the original substance with concentrated sulphuric acid, and with hydrochloric acid. Compare § 245, 1, a. b. A PRECIPITATE IS FORMED: add solution of potassa or soda, drop by drop, until the fluid manifests a strongly alkaline reaction. a. The precipitate redissolves. Absence of the alkaloids of the second and third groups. Presence of MORPHIA is indi- . cated. The reactions with iodic acid (§ 235, 9), and with sulphuric acid, &c. (§ 235, 7), are resorted to as conclusive tests. Examination for salicine, see 4.

6. The precipitate does not redissolve, or at least not completely. Filter, and treat the precipitate as directed in 2. Saturate the filtrate with carbonic acid, or mix it with bicarbonate of soda or bicarbonate of potassa, and boil nearly to dryness. Treat the residue with water; if it dissolves completely, this is a sign that no morphia is present; but if there is an insoluble residue left, this indicates the presence of morphia. The reactions with iodic acid (§ 235, 9), and with sulphuric acid, &c. (§ 235, 7), are resorted to as conclusive

tests.

2. Wash the filtered precipitate of 1, b, 2, with cold water, dissolve in a slight excess of dilute sulphuric acid, and add solution of bicarbonate of soda to the fluid until the acid reaction is neutralized; stir the mixture, vigorously rubbing the sides of the vessel, and allow the fluid to stand for an hour.

a. No PRECIPITATE IS FORMED. Absence of narcotina and cinchonia. Boil the solution nearly to dryness, and treat the residue with cold water. If it dissolves completely, pass on to 4; but if an insoluble residue is left, examine this for quina-of which a minute quantity might be present-and for strychnia, brucia, and veratria, according to the directions of 3.

b. A PRECIPITATE IS FORMED. This may contain narcotina, cinchonia, and also quina, compare § 245, 2, b. Filter, and treat the filtrate as directed § 246, 2, a. Wash the precipitate with cold

water, dissolve in a little hydrochloric acid, add ammonia in excess, then a sufficient quantity of ether.

a. The precipitate which forms at first upon the addition of

the ammonia redissolves completely in the ether, and the clear fluid presents two distinct layers. Absence of cinchonia; pre sence of quina or narcotina. Evaporate the ethereal solution, dissolve the residue in a little hydrochloric acid and a sufficient amount of water to make the dilution at least as 1: 200; add bicarbonate of soda to neutralization, and allow the fluid to stand for some time. The formation of a precipitate indicates the presence of NARCOTINA. Filter, and test the precipitate with chlorine water and ammonia, and with a mixture of sulphuric acid and nitric acid (§ 236). Evaporate the filtrate, or the fluid if no precipitate has formed, to dryness, and treat the residue with water. If part of it remains undissolved, wash this, dissolve in hydrochloric acid, and add chlorine water and ammonia. Green color: QUINA.

B. The precipitate produced by the ammonia does not redissolve in the ether, or at least not completely: CINCHONIA. Quina or narcotina may also be present. Filter, and examine the filtrate for quina and narcotina as in a. The precipitate consists of cinchonia, and may be further examined according to § 238, 3, or 8.

3. Wash the insoluble residue of § 246, 2, a, with water, dry on the water-bath, and digest with absolute alcohol.

a. IT DISSOLVES COMPLETELY: absence of strychnia; presence of (quina) brucia or veratria. Evaporate the alcoholic solution on the water-bath to dryness, and, if quina has already been detected, divide the residue into two portions, and test one part for BRUCIA, with nitric acid and protochloride of tin (§ 241, 6), the other for VERATRIA, by means of concentrated sulphuric acid (§ 242, 6); but if no quina has as yet been detected, divide the residue into three portions, a, b, and c; examine a and b for BRUCIA and VERATRIA, in the manner just stated, and c for quina, with chlorine-water and ammonia. However, if brucia is present, dissolve e in hydrochloric acid, add ammonia and ether, let the mixture stand for some time, evaporate the ethereal solution, and examine the residue for quina.

b. It does not dissolve, or at least not completely: presence of STRYCHNIA; perhaps also of (quina) brucia and veratria. Filter, and examine the filtrate for (QUINA) BRUCIA and VERATRIA as directed § 246, 3, a. The identity of the precipitate with strychnia is demonstrated by the reaction with sulphuric acid and chromate of potassa (§ 240, 8).

4. Mix a portion of the original solution with hydrochloric acid, and boil the mixture for some time. The formation of a precipitate indicates the presence of SALICINE. To set all doubt on this point at rest, test the original substance with concentrated sulphu ric acid (§ 244, 3).

III. DETECTION OF THE ALKALOIDS, IN PRESENCE OF COLORING AND EXTRACTIVE VEGETABLE OR ANIMAL MATTERS.

§ 247.

The presence of mucilaginous, extractive, and coloring matters renders the detection of the alkaloids a task of considerable difficulty. These matters obscure the reactions so much that we are even unable to determine by a preliminary experiment, whether the substance under examination contains one of the alkaloids we have treated of in the foregoing paragraphs, or not. I will now give several methods by means of which the separation of the alkaloids from such extraneous matters may be effected, and their detection made practicable. Which of these methods to select will, of course, always depend upon the particular circumstances of the case.

1. STAS'S METHOD FOR EFFECTING THE DETECTION OF POISONOUS ALKALOIDS.*

This method is based, a, upon the solubility of the acid salts of the alkaloids in water and in spirit of wine; b, upon the fact that the alkaloids, even those sparingly soluble in ether, will pass into the ethereal solution upon mixing the aqueous solution of any of their salts with a fixed alkali or with the carbonate of a fixed alkali in excess, and shaking the mixture repeatedly with ether;-lastly, c, the removal from the alkaloids of other matters soluble in ether, is based upon the insolubility of the salts of the alkaloids in ether, owing to which an aqueous solution of the acid sulphate of the alkaloid can be obtained, by shaking the ethereal solution of the pure alkaloid with dilute sulphuric acid. I will give here, first the original method of STAS, then, in 2, Orro's modifications of that method.

a. If you have to look for the suspected organic bases in the contents of the stomach or intestines, or in articles of food, or in pappy matters in general, heat the suspected substance with double its weight of strong alcohol, acidified with from 0·5 grm. to 2 grin. of tartaric acid or oxalic acid, to from 158° F. to 167° F. When quite cold, filter, and wash the undissolved part with strong alcohol, adding the washings to the filtrate.

If you have to deal with the heart, liver, lungs, or similar organs, cut them into fine shreds, moisten with the acidified alcohol, press, and repeat the same operation, until the soluble parts are com pletely extracted; collect the fluids obtained, and filter.

b. Concentrate the alcoholic fluid at a temperature not exceeding 95° F., and, if no insoluble matter separates, continue to evaporate

"Bulletin de l'Académie de Médecine de Belgique," IX. 304. "Jahrb. f. prakt Pharm.," XXIV. 313. Jahresbericht" von Liebig und Kopp, 1851, p. 640.