the evaporation of this menstruum, the crystals of caffeina were obtained perfectly free from color.

In repeating this process for the purpose of estimating the quantity of caffeina contained in a specimen of guarana procured from the Brazilian collection at the Centennial Exhibition, the difficulty of separating the solution from the portion insoluble in boiling water, and the tediousness of the process of washing the mass precipitated by the acetate of lead solution led me to seek some other method by which these impediments might be avoided, and therefore determined to attempt the separation by means of litharge, which substance has been highly recommended ("Amer. Jour. Pharm.," 1875, p. 135) by Prof. E. S. Wayne, for the extraction of caffeina from tea and coffee. The result, confirmed by several trials of the process, proves that this compound of lead answers equally well for guarana, and that by its employment the quantitative determination of the caffeina in this substance can be effected with the utmost facility.

The details of the method are as follows: the powdered guarana is intimately mixed with three times its weight of finely divided litharge, and the mixture boiled in distilled water, the ebullition being continued until, on allowing the temperature to fall below the boiling point, the insoluble portion is found to subside rapidly, leaving the supernatant liquid clear, bright, and without color. The quantity of distilled water required will be found to be about a pint for every fifteen grams of the guarana used in the experiment, and, as the boiling has to be continued for several hours before the desired and all essential separation mentioned above takes place, water must be added from time to time to supply the place of that lost by evaporation. When cool, the clear liquid is decanted upo na filter, and when it has passed through, which it will be found to do with facility, the precipitate is to be transferred to the filter and washed with boiling water, the washing to be continued as long as yellowish precipitates are produced with either phosphomolybdic acid solution, auric or platimic chloride. A stream of sulphuretted hydrogen gas is now passed through the filtrate to remove the small quantity of lead that has been dissolved, and the sulphide thus formed separated by filtration. The solution is evaporated on a water bath to expel the excess of sulphuretted hydrogen, filtered to remove a trace of sulphur, finally evaporated to the crystallizing point, and the caffeina, which crystallizes out on cooling, removed. from the mother liquor and pressed between folds of bibulous paper. After being thus treated the crystals will be found to be perfectly white. On diluting the mother liquor with distilled water, filtering and evaporating, a second crop of crystals are obtained, which are also perfectly white, after being pressed as above. The crystals are now dissolved in boiling diluted alcohol, filtered, and the solution. set aside to crystallize by spontaneous evaporation. The resulting crystals of caffeina are perfectly pure and colorless.

In order to test the accuracy of the process, fourteen grams of guarana in an impalpable powder were treated with the utmost care, as above described. The extracted caffeina, after drying at 100° F. until the weight became constant, was found to weigh .707 grams, 5.05 per cent., a remarkably close approximation to the results of Stenhouse, who, from 25 grams of guarana, obtained 1.260 grams of caffeina =5.04 per cent., and from 14 grams 5.1 per cent. Average 5.07. =

As this method of extracting caffeina is entirely devoid of all complicated steps, and requires but a short space of time for its completion, it may be used advantageously in estimating the percentage of caffeina in the fluid extract of guarana, which is prescribed to a certain extent at present, and may possibly be more extensively used in the future.

In regard to the proper accentuation of the name of the substance prepared from the seeds of the Paullinia sorbilis, by the Indian tribes on the upper Amazon, I would state that throughout Brazil, and in all parts of South America, where the preparation is used, the word is universally accented on the last syllable, guaraná, and never pronounced guarána, the popular method of accenting the term in this country. The placing of the accent on the last syllable in words ending in a is not all unusual in the Guarany language; for instance, as regards localities, Paraná and Ceará, retain their Indian accentuation; and in the vegetable world, the Caladium esculentum is always spoken of as the Taja or Taya, the Franciscea uniflora as the Manaca, and the Gomphia parviflora, as the Baptiputa.

DR. OSCAR LIEBREICH ON CHLORAL.*

After some remarks on impurities in general, Dr. Liebreich goes on to say:

I have good reason to believe that a large proportion of the chloral, both solid and liquid, which is at present employed in medicine is not trustworthy in respect to its purity. I am, moreover,

well assured, and I wish to draw the attention of practitioners to this point, that many of the impurities of chloral, when it is not prepared with great strictness and tested with scrupulous accuracy, are of a kind seriously to detract from its uniformity of effect.

Such impurities are calculated to have both a directly and indirectly mischievous effect. Directly, because some of these impurities contravene the simply hypnotic and anesthetic powers of chloral, and confer upon the so-called chloral with which they are mixed irritating and exciting properties; indirectly, because by ren* From the Practitioner, in the Chemist and Druggist.

dering the chloral in certain cases feebly hypnotic, they render the practitioner or the patient uncertain of the proper dose; they lead to multiplication of doses, and, in consequence, they tend to produce fatal results. The comparative inertness of the first doses leads to the re-duplication of the dose at too frequent intervals, until suddenly a fatal result is produced. The accidents which have occurred frequently in England are, I am satisfied, largely due to the impurities and uncertainty of the many preparations, and especially of many of the solutions in vogue. A study of the nature of these impurities is therefore just now imperatively called for.

Without entering on the history of chloral, we may remind ourselves that it was first discovered by Liebig in 1830. and that the product was always a cake chloral, with very numerous impurities. It is altogether impossible to purify this cake chloral. It is, however, now known by what process to produce clearly crystallized chloral in dry transparent crystals, which are free from the impurities, these being held in solution in the mother-liquor. Such crystals alone are reliable. Crystals of chloral hydrate which are not dry and transparent are not at all trustworthy.

In one of the most recent and justly reputed treatises on materia medica, published in England, I find the characters of chloral described thus:-" In colourless crystals (needles or acute rhomboidal plates)." I must, however, observe that chloral hydrate in needles is quite unworthy of the confidence of the practitioner. It may very well be, and is very likely to be, another chlorated substance, or very impure chloral hydrate. In America especially these impure forms of chloral hydrate are largely in favour, and everywhere there is a tendency to employ them where the consideration of relative cheapness in wholesale quantities is an element in the decision, and where the dangers of even apparently slight impurity in chloral hydrate are not adequately recognized.

The chloral hydrate which is not perfectly pure may sometimes be observed to become more acid. This increase of acidity is not due to the decomposition of the chloral hydrate itself, but to the decomposition of an accompanying impurity (chloro-carbonic acid) which sets free hydrochloric acid. When this occurs in the stomach it gives rise to great irritation, and I believe that when it occurs in the blood it causes great constitutional excitement. Hydrochloric acid is not in itself dangerous; but in these cases it is the indication of the existing impurities which give rise to hydrochloric acid by their decomposition, and which are, as clinical experience proves, in themselves irritating and dangerous. Thus, if a physician make the experiment of giving a dose of pure chloral hydrate with a little hydrochloric acid, and of giving a dose of the impure chloral hydrate which produces hydrochloric acid by decomposition as I have mentioned, he will find a great difference; in the first case, he will get the true hypnotic results of chloral hydrate; in the latter he will find symptoms of cerebral excitement and nervous irritation.

A more intense, and often a very different effect, is produced when a toxic substance is produced by decomposition within the blood, and in direct contact with the tissues of the organism.

The observations of Dr. Russell on the excessive alkalinity of the blood in typhoid fever have an extremely interesting chemical relation to the clinically observed fact that chloral hydrate is extraordinarily potent in its effects in that disease, and must be administered only in very small doses during the stages of excitement and delirium in the disease: its effects in such doses, however, being the more useful that opium is contraindicated. Ten grains of chloral hydrate will often suffice to produce hypnotic effects, while in the stage of excitement of "delirium tremens one or two drachms are necessary.

On the other hand, I have seen cases of uric arthritis in which chloral hydrate in high doses produced great excitement without giving sleep after a full course of alkalies the effect became very different, ordinary doses of chloral producing sleep without excitement. This is in accordance with the general law, which is now well established and tried. I have often had occasion to insist that the best effects of chloral are developed only in a normally alkaline state of the blood; that its effects are heightened when the blood is excessively alkaline, and are counteracted by the opposite chemical conditions.

It has happened to me more than once that my professional colleagues have brought to my notice cases in which chloral hydrate has produced considerable nervous excitement; the state of excitation combating and, in some cases, overcoming the hypnotic effect. In investigating them I found that the chloral employed was of the impure kind of which I have spoken. On opening the cork irritating fumes arose; it was acid, and contained certainly a good deal of chloral, but with it other compounds which give rise by their decomposition to acid and irritating substances of complex character, which have a very injurious physiological action.

I do not at all consider that all cases of excitement arising from the administration of chloral are necessarily due to impurity of the chloral; for imperfectly alkaline conditions of the blood may, as I have said, produce such effect, and other causes also. I may mention also a curious effect of pure chloral which I have observed in several cases. It sometimes happens that if a person who has taken chloral takes alcohol at a subsequent repast, the superficial vessels become dilated, and there is great flushing of the face, as though an excessive amount of alcohol had been taken. I cannot explain this vascular dilatation; but in such cases it may be necessary for the patient to discontinue either the alcohol or the chloral.

Dr. Liebreich would, therefore, altogether prohibit the use of chloral, either in solution or otherwise, which is not of the utmost purity. There is no practical means by which the purity of chloral

in solutions can be ascertained; and the best authorities state that a very large proportion of the solutions current in medical and pharmaceutical practice are of an impure, untrustworthy character, and therefore liable to produce dangerous results. To produce the best effects of chloral it should not be given on an empty stomach. It is not necessary that a full meal should have been taken, but it is desirable that some light nourishment or a biscuit, or something of the sort, should be eaten before the dose of chloral is administered.

THE MANUFACTURE OF AMMONIA SALTS FROM THE AMMONIACAL GAS LIQUOR.*

The following method of preparing ammonia salts from the gas house waters, by means of soda salts, is particularly interesting, since it produces a pure carbonate of soda at the same time, and is both cheaper and easier than the Solvay soda process; and it involves no waste products. Dr. G. T. Gerlach, of Kalk, near Deutz, is the inventor of the process.

If sal ammoniac is the salt we wish to obtain, chloride of sodium (table salt) is of course the source of the chlorine, and the process resembles in some respects that of Solvay. The crude ammoniacal liquors are first distilled and yield carbonate of ammonia; in this is dissolved a quantity of common salt, equivalent to that of the carbonate of ammonia present. This solution has a gravity of 122. Into it is passed a current of carbonic acid gas, as long as any bicarbonate of soda is precipitated. Some sulphurretted hydrogen is thus expelled, which had passed over in the form of sulphide of ammonia. The precipitated bicarbonate of soda is removed and dried; and on heating, enough carbonic acid is expelled to serve for the next operation, monocarbonate of soda remaining. The liquid contains chloride of ammonia with some undecomposed carbonate of ammonia, with cloride of sodium and a little dissolved bicarbonate of soda. The carbonate of ammonia is recovered by distillation, the sal ammoniac and salt by crystallization after concentration. Instead of being decomposed by lime, as in Solvay's process, the sal ammoniac is sent to the market. If, however, it is desired to make aqua ammonia, some of this mother liquid is treated with lime and distilled.

If sulphate of ammonia is the product desired, the sulphate of soda is employed to decompose the carbonate of ammonia. Either crystallized Glauber salt is dissolved in the concentrated solution of carbonate of ammonia, or the anhydrous sulphate (salt cake), obtained in the manufacture of nitric or hydrochloric acid, is dissolved in, a less concentrated solution of the ammonia salt. Equivalent * Scientific American.