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BRITISH AND AMERICAN MEDICALJOURNALS.

CONTRIBUTIONS TO THE DIAGNOSIS AND PATHOLOGY OF CHEST

DISEASES.

UNDER this title Dr. MacDonnell offers some valuable facts

and observations in the last number of the Dublin JournaL At

page 75 of the first volume of THE LANCET for last year, we gavean analysis of an essay, by the same gentleman, on the.. Diagnosis of Empyema." Of this form of disease his presentcommunication affords another example. This case is chieflyremarkable for the close resemblance which it presented in its

origin, in its general symptoms, and in many of its physical signs,to tubercular consumption. There were present, emaciation,purulent expectoration, hectic fever, mucous rales at the apex ofthe affected side of the chest, and various other signs, which wouldat once have led a superficial or ignorant inquirer to arrive atthe most unfavourable prognosis. A sound knowledge of thephenomena of chest pathology discovered, however, sufficient

grounds for a different conclusion, and the disease was pro-nounced to be Empyema. The progress of the case, and the final

recovery of the patient, afforded the most satisfactory evidence ofthe accuracy of this opinion.On the history of this, and of eight other cases of empyema,

the author founds the following proposition:-" That purulent expectoration in empyema, though attended by

quick pulse, sweating, emaciation, and other hectic symptoms, isnot indicative of tubercular or pneumonic abscess, unless accom-panied by unequivocal physical signs of these lesions; but, onthe contrary, it is to be regarded as the consequence of an effortof the constitution to get rid of a large collection of matter byone of the ordinary emunctories."

Gangrene of the lung also might have been supposed to havebeen present in this case, as the breath and expectoration wereextremely foetid. The same characters were also present in

certain other cases, which terminated fatally, showing that nosuch condition of the lung existed. Dr. MacDonnell offers the

following, and, we believe, correct explanation of the phe-nomenon:-

" In such cases, we have a quantity of pns and air occupyingthe minute tubes and air cells, and having but an imperfect com-munication with the external atmosphere, owing to the larger tubesbeing nearly obliterated by the compression to which the lung is

subjected by the fluid of the empyema, and in this way they actchemically on each other, and produce a decomposition, givingrise to the intolerable odour which both the pus and expired airsoon acquire. In fact, the same phenomena are observed inthese cases as in an ordinary abscess, the matter of whichmay be healthy and odourless on its being opened, but soon be-comes altered in these respects when air enters the sac and actsupon its contents, which then become bad in quality and offen-sive in odour. This view is borne out by what was noticed in thepresent case-viz, that the breath was not foetid during ordinaryexpiration, but became so immediately after coughing, by whichthe air pent up in the remote tubes was expelled, whilst thattaken in during ordinary inspiration was exhaled devoid ofodour."A bruit synchronous with the heart’s action was heard during

the progress of the case, at the left side of the spine. It disap-peared with the effusion. Further investigation will probablyshow this to be a sign of some importance in acquiring informa-tion as to the actual physical relations of the parts within thechest.

SIMPLE METHOD FOR ANALYZING THE BLOOD.

M. Figuier has suggested an easy method for the roughanalysis of the blood. By adding to one volume of defibrinatedblood two volumes of a solution of sulphate of soda, of sp. gr.marking 16° to 18° in Baume’s aerometer, the corpuscles willseparate, (as Berzelius shewed,) and may, with hardly an excep-tion, be all collected on a filter. Thus their quantity may beestimated, as that of the fibrine may (very roughly), by what isobtained by whipping. The quantity of albumen may be esti-mated by boiling the serum, and the water, by evaporating aseparate portion of blood.-British and Foreign Review.

CHEMISTRY, PHARMACY, ANDMATERIA MEDICA.

ON A NEW PROCESS FOR THE PREPARATION OF LIQUIDHYDRIODIC ACID.

BY MR. RICHARD PHILLIPS, JUN.

WISHING to repeat the experiment made by Dumas, of actingupon hydrated sesquioxide of iron by liquid hydriodic acid, Ifound considerable difficulty in preparing the acid of sufficientstrength, by the usual methods, without its undergoing decompo-sition.The process, I believe, generally adopted, is to pass a current

of hydrosulphuric acid gas through iodine suspended in water,sulphur being precipitated, and hydriodic acid formed. Thesolution is then boiled, until all excess of the gas is got rid of,and the residue filtered.

It is, according to Berzelius, open to this objection, that, onaccount of the iodine being but sparingly soluble in water, it isnecessary continually to stir the solution, and that even if thisprecaution be taken, the iodine becomes so mixed with the pre-cipitated sulphur as to remain unacted upon by the hydrosul-phuric acid. To this I may add, that when the solution is boiled,to get rid of the excess of the gas, or evaporated, to increase its

strength, by the decomposition of hydriodic acid when exposedto the action of the atmosphere, a small amount of iodine is setfree, as shewn by the blue colour given by starch to the solution.

In Professor Kane’s Elements of Chemistry, it is stated, that ifdilute sulphuric acid be added to a solution of iodide of barium,sulphate of barytes is precipitated, and hydriodic acid formed.The usual process, however, being to form iodide of barium byacting upon carbonate of barytes, or barytes-water, by hydriodicacid, nothing is gained by the operation. It, however, occurredto me, that I might succeed by adopting the same principle, butvarying the process. And my first experiment was to add toa solution of iodide of potassium in alcohol, hydrocholoric acid ;chloride of potassium, and hydriodic acid were formed, andthe chloride being insoluble in the alcohol, was separated byfiltration. This method, however, I conceived, was objection-able, on account of the difficulty of adding exactly the rightproportion of hydrochloric acid, and that from the hydriodicacid acting upon the alcohol, hydriodic ether might be formed.I therefore substituted zinc for the potassium, and oxalic acid forthe hydrochloric acid, and these objections were removed. Thefollowing was the process :-To 126 grains of iodine mixed withabout one fluid ounce of distilled water were added thirty-fivegrains of zinc turnings. The action was aided by a gentle heat,(care being taken that the mixture was not exposed to atmo-spheric air,) and when it had ceased, and no free iodine was foundto be present, the residual zinc was washed, dried, and weighed.The solution and washings were then evaporated, and with themwas mixed for every atom or thirty-two grains of zinc found tohave been dissolved by the weight of the residual zinc, one atomor sixty-three grains of crystallized oxalic acid. The mixturewas gently heated, and when cold, the precipitated oxalate ofzinc was separated by filtration, and the hydriodic acid containedin the solution was found to contain neither oxalic acid, zinc,nor free iodine.During the evaporation of the iodide of zinc, a slight preci-

pitate takes place, and the solution becomes acid, resulting, as Ihave before shewn, in the cases of the iodides and chlorides ofiron, from water being decomposed, hydriodic acid being set free,and oxide of zinc precipitated. This, however, makes no differ-ence in the accuracy of the process, as the oxalic acid wouldunite with the precipitated oxide of zinc.

In conclusion I may remark, that the advantages of this pro-cess would appear to be, tl.at by ascertaining the amount of zincdissolved, not the slightest difficulty arises in adding exactly theproper quantity of oxalic acid to precipitate it, and that from theevaporation of the iodide of zinc, previously to adding the oxalicacid, hydriodic acid of great strength is readily formed.-Pharm.Jour.

ADULTERATION OF JALAP ROOT.

Sometimes brown, ragged, pear-shaped fragments are foundmixed with the true jalap root, which resemble it very muchexternally, but are not so heavy, and are either soft and flexible,or readily broken when they have been roasted. In many pieces,fibres may be distinctly perceived, and from this, as also fromtheir sweet taste, they would seem to be dried fruit which hadbeen immersed in tincture of jalap, and have thus been rendered

somewhat acrid to the taste. Similar adulterations hare also been

observed in articles sent under the name of jalap root fromBremen.-Archiv. der Pha2-m., M. Ingenohl.