Retrospect of the Medical Sciences
BMJ (Clinical Research Edition)
I have, within the last few days, been led to try r the process for hydrosulphuret of ammonia, recomimended in the April number of your journal. The a object apparently is to get a protosulphuret of cals cium, and then to decompose it by means of sulphate I of ammonia, for the ingredients are all taken nearly in 1 atomic proportions. The reaction might, if this were I the case, be thus expressed: Ca S and N H4 0, I S Oa, and N H4 S. But nothing of this sort occurs, t because in boiling the lime
... in boiling the lime with the sulphur, no proto-f sulphuret of calcium is or can be formed but (leaving out of the question a little hyposulphite of lime which i is produced) the solution contains only a pentasulphuret of calcium, and, consequently, four-fifths of the lime are removed on filtration. The sulphate of ammonia being now added, in quantity equivalent to the whole of the lime, one-fifth only is decomposed, and the 4 following reaction occurs :-Ca Ss and N H4 0, I S 03,=Ca 0, S 03, and N H4 S + S4, the product I thus containing not only a great quantity of sulphate of ammonia in solution, but also a large excess of sulphur, much of which precipitates on dilution with distilled water, or even on standing twenty-four hours. These results I have obtained by experiment as well as theory, and yet the solution is described as " sufficiently pure for most experimental uses." If this be submitted to distillation, as recommended where perfect purity is required, the sulphate of ammonia and excess of sulphur are got rid of, and the product N H4 S in solution is obtained sufficiently pure; but this is not the same thing as that obtained by passing sulphuretted hydrogen through solution of ammonia, which is now generally allowed by chemists to have the formula N H4 S + H S. In fact, the dis. tilled liquid is precisely similar to that produced by the well-known old process of distilling together lime, sulphur, and muriate of ammonia, and known, when concentrated, as " Boyle's fuming liquid," which was constantly used as a test until recently superseded by the other preparation. The processes, too, differ only in this, that the newv one substitutes sulphate for muriate of ammonia, and employs three operations where one only is necessary.-Pharmaceu tical Journ. ETIOLOGY OF HYSTERIA. What is it that gives rise to this disturbed state of the nervous system in hysteria, to this abnormal state of the molecular relations, and this impairment of its chemical constitution-in one word, to this derangement of its nutrition ? The causes of hysterical phenomena are of two kinds, mental and physical. A morbid state of mind continually acting upon the nervous system is well suited to disturb the equilibrium of its nutrition. The physical causes are all such as must impair general nutrition, and thus favor the influence of any agent which would specially affect the nerves. Thus the want of good air, of proper exercise, defective secretions, derangements of primary assimilation, disturbed uterine functions, are the most common of these physical causes. These operate by impairing the healthy quality of the blood, and this pabulum of the tissues being injured, they must participate in the injury, and that tissue will suffer most in which physiological change is most active. In hysteria that tissue is the nervous which is disturbed by mental causes; its excited state of physiological action occasions a greater demand for the nutritive supply, and it, therefore, attracts a greater share than perhaps properly belongs toit of the imperfectly-formed blood. This primary disturbance of nutrition has, however, a yet more extensive influence, for the effete particles of the badly-nourished tissues, coming back to the blood, are likely to contaminate it to a still further extent. It oftenhappens, too, that a special morbid element is present in the blood in hysterical habits, which must interfere more or less with its healthy actions. Thus you often find hysteria and hypochondriasis in women and men of gouty or ofrheumatic constitution. This was the case in a marked degree in the woman Collier, who afforded a good example of hysterical paraplegia; she had the rheumatic diathesis to a great extent; although she never had rheumatic fever she had heart disease, and her hysterical paroxysms were always excited by the same causes which increased her rheumatic pains. It is worthy of remark, too, that during the menstrual age women seldom suffer from a fit of the gout, although the gouty diathesis may be sufficiently distinctly developed. But when they begin to have the gouty paroxysms, which provide for the elimination of the gouty matter from time to time, the hysterical phenomena become materially diminished.-Dr. Todd's Clinical Lecture. It is generally admitted by chemists as a fact that marble is not acted upon by nitric acid of the greatest density. M. B., desirous of ascertaining whether this anomaly was due to the same want of action of this acid on certain metals, kept a piece of marble in concentrated nitric acid, and it was not visibly acted upon. It was then removed from the acid, washed, dried, and powdered, and the powder was put into fresh concentrated acid. It was strongly acted upon, but not entirely dissolved. A little water was then added to the acid, the reaction again took place, and after some time ceased, but recommenced on the ad. dition of more water. It may be concluded from these facts that marble is attacked by concentrated nitric acid, with energy proportional to its surface, becoming covered with a varnish Of nitrate of lime, insoluble in concentrated nitric acid. This nitrate of lime concentrates the nitric acid in which it is produced, and renders it more strong. The experiment performed in a direct mode was perfectly conclusive; dried nitrate of lime put into nitric acid of moderate strength, concentrated, and rendered it fuming.