LECTURES ON ORGANIC CHEMISTRY;

743

SEPTEMBER 14, 1844.

LECTURES ON

ORGANIC

CHEMISTRY; 1844,

IN THE

DELIVERED DURING THE WINTER SESSION,

UNIVERSITY OF GIESSEN.

with

The amide of mercury formed, one

atom of

precipitates in combination

perchloride of mercury.

BY

JUSTUS LIEBIG. M.D., PH.D., F.R.S.,

M.R.I.A., Professor of Chemistry in the

University

of Giessen.

AMIDOGEN.

The precipitate is a double compound, half of which consists of perchloride of mercury, the other of a combination of mercury with the amidogen of the compound substance ammonia; in the solution we have sal ammoniac, and in the precipitate amide of mercury in combination with perchloride of mercury. This substance is scantily soluble in cold water ; boiling water imparts a blue colour to it; when boiled with potass it undergoes

GENTLEMEN,-The formation of amide of potassium and amide of sodium has been mentioned already in a former lecture when treating of ammonia. I told you no apparent alteration, except in its colour, but upon on that occasion that ammonia is decomposed both by potassium and sodium; that these metals, when heated analysis it is found to have changed its composition. If in ammoniacal gas, evolve therefrom exactly as much the white precipitate consisted of a combination of oxide hydrogen as they would evolve from water if brought into of mercury, ammonia, and perchloride of mercury, boilcontact with it; that is, one equivalent of hydrogen, for ing with potass would very readily convert the remaining I further ex- perchloride into oxide of mercury, and would as readily one equivalent of potassium or sodium. plained to you that the substance formed by heating po- expel the ammonia, but this is not the case; by boiling the tassium in ammoniacal gas is an easily fusible mass, white precipitate with potass we do not carry its decomconsisting of potassium combined with a compound of position further than this; the simple boiling with water nitrogen and hydrogen, to which latter the term AMI- changes, as already mentioned, the white colour of the BOGEN has been assigned, precipitate into yellow; the same alteration in colour takes place if the white precipitate is boiled with potass, but the new yellow precipitate contains the following This action of potassium upon ammoniacal gas, by which the latter is decomposed, has been known for the last years. It was treated of by Gay Lussac and Thenard, and by Sir H. Davy, but the true nature of the new-formed compound and its chemical deportment, remained almost without notice ; at any rate, it exercised no influence upon our views and notions until Dr. Kane analysed that pharmaceutical preparation known as white

forty

precipitate.

White precipitate is excess to a solution of

prepared by adding ammonia in perchloride of mercury (corrosive

sublimate). Those chemists who analysed white precipitate previous to the investigation of Kane, supposed it consisted of a double combination of oxide of mercury, ammonia, and ".],l"";n,, nf

m""f>l1"V’-

If potass is added to a solution of corrosive sublimate, but not in sufficient quantity to impart an alkaline reaction to the solution, a double salt is obtained consisting of nerchloride and oxide of mercurv.

compound :It may be considered

as a

combination of white

preci-

pitate plus oxide of mercury; only part of the ammonia is evolved upon the boiling with potass. White precipitate is very readily decomposed by soluble sulphuret as sulphuret of potassium and and also by iodide of potassium. It is but scantily soluble in water, but exceedingly so in certain ammoniacal salts, as, for instance, in nitrate and acetate of ammonia with excess of ammonia. If you precipitate sulphate or nitrate of mercury with ammonia you equally obtain white precipitate, containing (which is remarkable) likewise amide of mercury, which in this instance is formed by the decomposition of oxide of mercury with ammonia. Thus, if you add ammonia to sulphate or nitrate, of mercury you obtain

There exists still another combination of chloride of mercury with ammonia, viz., that which goes by the name offusible white precipitate. If you expose the white precipitate which forms upon the addition of ammonia in This is a crystalline powder of a reddish colour. Bicar- excess to solution of perchloride of mercury to the action bonate of potass and lime-water also precipitate this of heat, it assumes a grey tint, volatilises without fusing, double salt from solution of corrosive sublimate when and the sublimate consists of mercurius dulcis. This is the heated. The precipitate obtained upon adding ammonia characteristic property by which we invariably recognise to solution of perchloride of mercury is white. It was true white precipitate. Considering white precipitate to be a double compound supposed to be a combination of the oxychloride with ammonia. of perchloride of mercury and amide of mercury, we have, if we assume the elements of the amidogen taken away, protochloride of mercury, Cl Hg left; upon The investigations of Kane proved indubitably that the applying dry heat to the white precipitate the amidogen white precipitate contains no oxide of mercury, but that is decomposed ; at first ammonia and hydrogen are obit is a compound of perchloride of mercury and amide of tained, and there remains N Hg besides Cl Hg, but N Hg is likewise decomposed, and thus ultimercury, the latter being a combination of mercury with finally this the same substance which we obtain by the action of mately protochloride of mercury Cl Hg formed. ProWohler, during his official visitation, for the purpotassium upon ammonical gas. The process of formation fessor of pose inspecting the pharmacies of the kingdom of is this :Hanover, found very frequently instead of the true white precipitate the fusible compound I have above alluded to, and which is formed when upon precipitating solutions of perchloride of mercury with ammonia there is no excess of the latter substance. The substance formed under such and hydrochloric acid Cl H, which combines with the circumstances is also a white precipitate, but its composition is very different from that of the true white nrefree ammonia, forming sal ammoniac.

744

cipitate ;

it contains the elements of two

mercury and one

perchloride of

ammonia,

and thus contains twice

as

much chlorine as the real

white precipitate, and likewise one equivalent of hydrogen more than the latter. Now, what is very remarkable, this substance is quite insoluble in water; when heated in the dry way it sublimes without undergoing any alteration. No investigation has as yet been made with regard to the constitution of this substance; all we know is that it may be produced in the dry as well as in the humid way. If you expose dry perchloride of mercury to the action of ammoniacal gas the perchloride absorbs the ammoniacal gas in the proportion of one equivalent of ammonia to two equivalents of perchloride of mercury, and the new-formed compound is not decomposed by distilling it by itself, nor by boiling it with water.

ANEURISMAL TUMOUR OF THE UPPER PART OF THE LEFT ARM.

By

ALFRED

JUKES, Esq., Surgeon Hospital.

to

the

Birmingham

NOVEMBER 22, 1824. Isaac Walters, a robust man, aged twenty-four, by trade a wood-screw forger, and whose height is five feet seven inches and a half, was admitted into the Birmingham General Hospital, from Burton-upon-Trent, with a tumour of irregular shape occupying the shoulder and the upper and back part of the left arm. Previous History.—More than four years ago, whilst intoxicated, he was stabbed in the back part of the left shoulder with a dagger about seven inches long. He fell from the violance of the blow, and copious haemorrhage ook place from the wound, which induced fainting. As lie revived the bleeding recurred. Professional aid having been procured, and a variety of proceedings adopted for suppressing the haemorrhage, the wound was at length closed by adhesive straps. The dressings were allowed to remain undisturbed for two or three days, when the shoulder and upper part of the arm had become so swollen and painful that the plasters were removed and a poultice substituted. This having no effect, the adhesive straps were again applied after a few days, and some compression was made over the parts by a bandage. About a week after the infliction of the wound the swelling suddenly, and without previous pain, enlarged rapidly for two days, and then as rapidly subsided. In three weeks the wound had healed and the swelling had disappeared, with the exception of a tumour at the upper part of the arm, as large as a hen’s egg, the exact position of which is not recollected by the patient. Neither the tumour nor the arm was painful, but on using the limb he was sensible of a weakness near the insertion of the deltoid muscle, and a general diminution of strength in the whole arm. From this period until September, 1824, the tumour slowly increased, at which time it suddenly enlarged in a direction downwards and outwards towards the arm, advancing, at the same time, but slightly on the inner side. He now also became sensible of a faint pulsation in the swelling, which was rendered so distinct by exercise that he was conscious of it without applying his hand over it. It continued its rapid growth up to the time of his admission, pulsating slightly and feeling weak during repose, but after exertion beating violently and aching severely about the shoulder. Ten weeks before he came to the hospital these symptoms were so acute as to compel him to abandon his employment. Present State.-The tumour reached from the upper and back part of the left shoulder, along the posterior and inner side of the arm, to its lower third. Its surface presents three distinct prominences : a superior, occupying the situation and having the form of the deltoid muscle, which has a firm dense feel ; a middle, the most projecting, somewhat below and behind the first, which is very tense and elastic, and is separated from the inferior eminence by a superficial channel, and which, when united with the lower prominence, extends to the inner part of the limb, where they form one large swelling.

This projection is most distinctly visible in front when the elbow is raised to a level with the shoulder. The irregularity of surface appears to have depended upon the position of the tumour. Above it is deeply situated beneath the deltoid muscle, which is pushed outwards, but presently emerging from the posterior edge of this muscle it becomes more superficial and protuberant, and evidently lies upon the outer head of the triceps. As for the slight groove between the middle and inferior portions, that probably depends upon the original form of the tumour. The greatest length of the mass is rather more than six inches, and its circumference, where most

fully developed, fifteen inches, the arm being necessarily included in the latter admeasurement. A firm semilunar circatrix, about one inch and a half long, with the concavity turned towards the spine, marks the spot where the dagger had penetrated. It is situated nearly midway between the top of the shoulder and the back of the axilla, one inch below the spine of the scapula, and nearly three inches from the acromion process, measured obliquely downwards towards the spine. It is not in the least painful when touched. The tumour did not pulsate during the patient’s residence in the hospital. Firm pressure, so as to stop the pulse at the wrist, applied to the subclavian or axillary artery, lessened the tenseness of the tumour, and by compressing the lower portion at the same time, a still further diminution of its bulk was effected, and it became one inch smaller in circumference than when the circulation was free. Upon removing the pressure from the artery, the compression of the tumour being maintained, the hand was raised by the immediate expansion of the swelling to its original size. The rising of the tumour was distinctly felt during the act of expansion, which occupied two or three seconds of time, and the blood appearedto enter it at its upper part. Pressure on the brachial artery below the tumour produced no perceptible change in it. A curious sensation, likethe buzzing of a fly in a phial, was felt at a spot about one inch perpendicularly below the sternal end of the clavicle, and was most distinct when the tumour was compressed below. The whole tumour was free from pain when handled. The impulse of the heart and the pulse at the wrist were natural, and no marked difference existed between the radial pulses of both sides. The brachial artery could be traced to the axilla unconnected with the tumour. The skin covering the tumour was of its natural colour, and the superficial veins were not enlarged. A dull aching pain was experienced after exercise, the fingers were slightly benumbed, and there was a deficiency of muscular power in the left arm. The general health was good. Measurements of the Tumour.—From the front of the humeral end of the clavicle obliquely backwards to the place where the dagger entered, 4 inches. From the same point to the posterior and upper boundary of the tumour, 5g inches. From the same point to the lower boundary on the triceps, 9 inches. From the cicatrix to the lower edge of the tumour, 8 inches. Circumference of the left arm at its middle third, and, consequently, including part of the tumour, 14 inches. Circumference of right arm at the same point, 10 inches. The tumour measured laterally, from its boundary on the inner side of the arm to its external boundary on the outer side of the arm, 8a inches. From the history of the case, and from the signs which have been detailed, the tumour was decided to be aneurismal, and it remained to determine by what vessel it was supplied. The brachial artery could be traced to the axilla, pulsating naturally and having no connection with the tumour. Compression of the axillary artery just below the clavicle rendered the swelling flaccid. Hence it appeared that the tumour did not arise from any part of the direct course of the axillary or brachial arteries, but that it was supplied from some branch of the former vessel. Of these branches, two only were so situated as to be exposed to injury from a wound taking the course described, namely, the posterior circumflex and the subscapular, and of these it seemed most probable that the latter was the vessel wounded. The disease was concluded to be diffused false aneurism of the subscapular artery, and it was determined to apply a ligature around the axillary artery, immediately