they were cut up, bruised and subjected to pressure in a onescrew press; the residue was moistened with water and again expressed; the liquid was heated to boiling and strained. On tasting it now for the first time, it was found to have a sweetish taste, entirely destitute of bitterness. If Aubergier examined the juice of L. elongata, prepared in the same way, this experiment agrees entirely with his result; but the press cake possessed the persistent bitterness of lactucarium.

It is probable that the milky juice of this species, on assuming so readily a tenacious gelatinous form, envelopes the bitter principles and prevents them from being removed with the sap by pressure. This theory would indicate a process for a reliable pharmaceutical preparation, on the merits of which, however, only actual experiments can decide.

QUERY 31.-Does the addition of metallic iron or zinc to ordinary hydrochloric acid, which contains sulphuric acid as an impurity, decompose the sulphuric acid and liberate sulphide of hydrogen?

In a discussion of the subject of tincture of the chloride of iron, imperfectly reported at page 97 of the Proceedings of last year, the writer stated, as an observed fact, that the escape of sulphide of hydrogen upon dissolving iroa or zinc in hydrochloric acid was an indication of the presence of sulphuric acid as a contamination of the hydrochloric acid, and was a good practical test for detecting sulphuric acid. Mr. Maisch spoke doubtfully upon the accuracy of the statement, and in a subsequent conversation expressed a decided conviction that it could not be true. The writer had seen the proposed reaction so often that he had had no doubt upon the subject previous to Mr. Maisch's remarks, and then proposed to try the point by direct investigation. With this end in view the writer proposed the question as one to be reported on this year, and accepted the investigation for himself.

The investigation has been carefully made, and proves that the escape of sulphuretted hydrogen during the reaction in question is no evidence whatever of the presence of sulphuric acid, and therefore that the statement of the writer was entirely erroneous, and Mr. Maisch was quite right upon the point of accurate knowledge which he raised.

It became then a matter of interest to the writer to ascertain how the error had occurred. This was satisfactorily determined, and may interest the Association as a part of the history of the hydrochloric acid of commerce.

This acid is often, if not generally, made by the best makers by decomposing common salt in iron retorts by means of sulphuric acid and heat. The gaseous products and vapors from the decomposition are conducted into a series of three or four receivers or Wolf's bottles containing water for the absorption of the hydrochloric acid gas. But the entering tubes of these receivers do not dip into the water as in the ordinary Wolf's arrangement, and the absorption of the gas is therefore slow and passive, only facilitated occasionally by stirring. From the last receiver an ascending series of four or more shallow glass vessels lying upon an inclined plane, and discharging by gravitation one into the other, and the lowest one into the last receiver, are so placed as to receive at the highest end supplies of fresh water from time to time. This water, flowing downward, meets the current of yet unabsorbed gas from the last receiver, and absorbs it all in its progress into the last receiver, which finally contains the best hydrochloric acid of the process, and of the common market. This, when put up for the market, often shows little or no sulphuric acid by the manufacturer's test, which is solution of chloride of calcium. The reaction which occurs in the castiron retort from impure materials, and at a high temperature at the close, gives various gaseous products, among which the most common and most copious are the lower oxides of sulphur. It has generally been supposed with reason that small quantities of sulphuric acid also distil over, and that thus the hydrochloric acid becomes contaminated with sulphuric acid. This is doubtless always true with regard to the contents of the first receiver, but is practically impossible to any after the second! Not so

with regard to the lower oxides of sulphur, however, some of which are gaseous and all far less easily condensed. These are, therefore, found in the farthest and coolest receivers, and escape detection by the chloride of calcium test. The hydrochloric acid, which when freshly made contains these lower oxides of sulphur, but no sulphuric acid, will, however, on keeping, soon begin to show sulphuric acid, and finally will contain this acid alone, all the lower oxides being progressively and spontaneously converted into the higher one.

When hydrogen is liberated in a nascent state in the presence of these lower oxides of sulphur, they are all reduced and converted into sulphuretted hydrogen, sulphur and water, leaving the solution comparatively free from sulphur compounds. Thus it happens that when freshly made hydrochloric acid, free from sulphuric acid, but containing the lower oxides, is used for making the chlorides of iron or zinc, the resulting chlorides will be free, or comparatively so, from sulphuric acid and sulphates, while a portion of the same acid, if kept long, will contain sulphuric acid and be comparatively free from the lower oxides of sulphur. Hence the escape of sulphuretted hydrogen during the reaction with these metals is an easy practical test for the lower oxides, but not for the higher.

This best grade of hydrochloric acid is often not accessible to the writer, unless he waits for it to be made, and then it is received quite fresh and new, and is at once used for making the chlorides of iron and zinc. It then gives off sulphuretted hydrogen so copiously that it is necessary to make the solution out of doors, and yields chlorides which are practically, though not absolutely, free from sulphates. Portions of the same lot of hydrochloric acid stored, and used subsequently, have been found to contain largely of sulphuric acid and nothing else. Hence the conclusion that nascent hydrogen decomposed sulphuric acid in this reaction and thus yielded the floating sulphur, and the escaping sulphuretted hydrogen was accepted on very insufficient grounds and erroneously put forth.

All of which is respectfully submitted in answer to Query No. 31.

Brooklyn, August 14th, 1868.

ON THE SALTS OF CONIA.

BY GEORGE C. CLOSE.

QUERY 33d.-Conia has been recommended as a therapeutic agent, but is liable to alteration from atmospheric oxygen As the salts of conia appear to be permanent and are odorless, why may not some of these be substituted for the alkaloid?

The assertion in the query that the salts of conia appear to be permanent, is contrary, I believe, to the authorities on the subject, except with regard to the muriate, which Prof. Wertheim asserts to be crystallizable and not in the least deliquescent. The method which he suggests for making the muriate is the combining the vapors of the two substances directly. This method, to be successful, would require a larger quantity of the conia than I could afford to use, as the cost is eight dollars for what purports to be an ounce of the article.

I succeeded in making a crystallized muriate by dissolving 30 grs. of the conia in 2 fluidrachms of dilute muriatic acid, previously diluted again with its bulk of water, and evaporating the solution by means of a water bath.

Heat is developed while dissolving the conia, and white vapors are evolved at first, which, even when the mixture is made in a well corked bottle, will sometimes escape partially.

Some of the crystals obtained by the evaporation of the mixture were exposed for several weeks in an open capsula. They became alternately wet and dry, according to the state of the weather. From this I infer that they are hygrometic but not deliquescent.

I swallowed half a grain of the crystals which had been so exposed (dissolved in water), without apparent effect. I then took one grain, which produced the characteristic effects of the conia to such an unpleasant degree that I should be loth to repeat the dose. I am far less susceptible to the action of conia than many persons. This seems to show that the salt will retain its medicinal properties after several weeks' exposure.

I did not succeed in obtaining a crystallizable salt with sulphuric, citric or oxalic acids.

The conia used was made by Merk. This appears to be the

only kind in market. Its quality is not uniform, as in some instances it will not all dissolve in the dilute acid, but an oily residue is left.

I presume the muriate of conia might be made directly from the fresh plant or fruit at less expense than the conia, and have no doubt but that it would be far more convenient and reliable for medicinal use than the latter.

I do not claim to have exhausted the subject of the query, and shall be very glad if some member who has more skill, more apparatus and more money will take it up and investigate it more thoroughly than I have done.

I present a sample of muriate of conia, probably not quite pure, but sufficiently so for practical purposes.

ON THE RELATIVE PROPORTION OF DIGITALIN PRESENT IN AMERICAN AND EUROPEAN DIGITALIS.

BY SAMUEL P. DUFFIELD, PH. D.

Last year I asked an extension of Query No. 34, viz. :

Do the leaves of the Digitalis purpurea grown in the United States yield less digitalin than the European plant? and is the alleged inferiority of the former, if this be true, due to a deficiency of this principle?

My reasons for asking an extension were that I had not, satisfactorily to myself, blocked out a method of procedure which would answer it best. I had designed estimating the quantity of the alkaloid digitalia by the proposed method of Mayer, by precipitation by means of iodohydrargyrate of potassium, or by Rudolph Wagner's method of iodine in a solution of iodide of potassium. The more I pondered, the more satisfied I became that that process would not give a satisfactory answer, as we have not yet investigated the combinations of the alkaloid with these reagents, and a good part of it would have to be (on my part) assumption. We have, however, given us in the Pharmacopoeia a method for the preparation of digitalin which is simple and practical. It is true it does not give us the pure alkaloid, but it gives it in a state pure enough for all pharmaceutical pur