the lime contained in the charcoal has given rise; and this salt, by altering the purity of the acetate of potash, retards its desiccation. It would, indeed, be very easy to separate it by adding a slight excess of carbonate of potash, in order to precipitate the lime; and we should afterwards put in an excess of acid but it is easier to saturate the acid first. The following is the process as described in the memoir: · Pour into distilled vinegar a solution of carbonate of potash, until no more carbonic acid is extricated afterwards evaporate the liquor, taking care always to keep an excess of acid in it: when it is reduced to threefourths, allow it to coul, in order to separate from it the sulphate of potash and some impurities; decant it in order to heat it, and pour it when hot on a charcoal filter.* If the filtered liquor does not contain more free acid, add a little distilled vinegar; + then evaporate to dryness; and if we wish to obtain the acetate of potash well cleaned, we must, at the end of the evaporation, manage the fire properly, and not stir it; but in this case it is not so white as when we separate it with a silver spatula, and throw it on the edges of the basin as fast as it is formed at the surface of the liquid: this salt will also be whiter if dried by small portious. On exposing for about twenty days to the solar rays the liquor filtered over charcoal, the author obtained a salt much whiter; hence he thinks that the same result might be obtained, by exposing to the light an acetate of potash made from distilled vinegar, without being filtered through charcoal. He regrets that he has been unable to collect some important facts relative to the colouring matter: he remarked that it was partly precipitated after saturation; that it is a little soluble in water, and that a portion remains in solution in the liquid acetate of potash that after having filtered distilled vinegar through very pure charcoal, like that which is produced from crystalized sugar, we no longer *The acetate of lime when dried is less deliquescent than the acetate of potash, and yet it is much more difficult to produce the desiccation of it.Note by the Author. A little acetic acid (radical vinegar) would be preferable; very little is necessary when care has been taken to filter the liquor in the neutral state: we must also take care that it is not acid, in consequence of the line which is in the charcoal, longer obtain, on saturating it with crystalized carbon ate of potash, the same precipitate as before filtration. The author of the memoir concludes, therefore, 1. That the colouring matter of the acetate of potash belongs to a vegetable substance contained in distilled vi negar. 2. That this colouring matter is destroyed by charcoal. 3. That an excess of aikali, when we evaporate the result of the saturation of distilled vinegar by potash, may influence the whiteness of the acetate of potash. 4. That in order to obtain the salt pure white and saturated, it is sufficient to filter a concentrated solution of it over a small quantity of charcoal in powder; to keep in it afterwards to the end of the evaporation an excess of acid, by adding from time to time distilled vinegar, and to expose it for some days to the solar light. In a note which terminates this memoir, the author says, that according to the valuable observation of M. ssrs. Vauquelin, Pontier and Derosne, he obtained two hectogrammes of excellent acetic ether, by rectifying over potash the first products of the disilation of 70 litres of distilled vinegar, The committee carefully repeated the experiments detailed in the above memoirs. If we except the whitening effects on exposing the acetate to the sun, which did not succeed with them, they pronounced them to be all cor rect; indeed, the principal agent in the whitening process was already known. Lowitz has recommended the us of charcoal, in order to obtain an acetate of potash less coloured than by the ordinary process; but whether he has not sufficiently described the method of using it, or employed vinegar of a bad quality, ill distilled or ill saturated, over which the depurating qualities of the charcoal had no influence, several chemists have been unsuccessful. From these considerations, and particularly from the satisfactory results obtained by the committee, they think themselves warranted in concluding, that the authors of the two memoirs would have done better by making. known the principle and the causes of the colouring of this salt, at the same time that they indicated the means of preventing and removing them. By following carefully the rules which they prescribe, and by taking all the precautions which they point out, we shall easily obtain, without having recourse to fusion, an acetate of potash very white and perfectly saturated. R 3 The The society has therefore decreed a gold medal of the va lue of 100 francs to each of the authors of the memoirs. The author of the memoir first mentioned is M. Bernoully of Bâle; and of the second, M. Fremy of Versailles. To the Editors of the Medical and Physical Journal. GENTLEMEN, I Believe it to be generally acknowledged by medical practitioners, that inflammatory diseases have been more prevalent within these few years than at any former period. To ascertain the cause of this is a task of a difficult nature, and I have not the vanity to suppose that any thing I can advance upon this part of the subject, will tend in the least to lessen that difficulty; it is generally understood that a plethoric habit of body is one of the predisposing causes to those diseases, but we find the spare delicate -frames of females almost as much subject to the influence of inflammatory diseases as the more stout and athletic of the male sex. Violent exercise is stated to be an ex-citing cause; but the indolent and inactive are no less liable to inflammatory attacks. The intemperate use of spirituous liquors is assigned as a frequent cause, and so it may be, in some instances, but yet the temperate are not exempt. I have had an opportunity of witnessing two or -three instances of this kind lately, in individuals who had invariably accustomed themselves to the most systematic and regular mode of living, labouring under violent inflammatory affections. The state of the atmosphere is generally resorted to as a dernier resource, when no other cause can be assigned, and perhaps this may be the most rational cause of all. The alterations of temperature observable in this variable climate, may certainly have great influence in deranging the actions of the human frame, and great care ought, at all times, to be observed to prevent the sudden application of either cold or heat. To be acquainted with the causes of disease, though gratifying to the physiological enquirer, is not absolutely of so much consequence as to be in possession of remedies capable of successfully combating those diseases. Till within late years, the internal and external exhibition of mercury was almost en tirely tirely restricted to the prevention and cure of syphilis; but as the nature of the disease became more investigated, and the action of mercury on the system better understood, practitioners of discernment have been disposed to try its effects in other complaints, and certainly with success. It is one of the late Mr. J. Hunter's physical axioms, that no two actions can exist in the same system, at the same time. If this is fact, and I am disposed to think it is from observation, with two or three exceptions, is it.not rational to suppose, that the action of mercury on the system, opens a wide field for improvement in the treatment of diseases? I have had the pleasure to observe its marked utility both in acute rheumatism and acute hepatitis; in both diseases, the same plan of treatment was adopted; in order to lower excessive action, bleeding was resorted to in the first instance, the extent to which it was carried, regulated by the rise, strength, and hardness of the pulse; the bowels were cleared. Mercury was then exhibited in appropriate doses, augmenting the dose till a slight ptyalism was produced; it became necessary in general to join an opiate with the calomel, in order to obviate its purgative effects on the bowels, and at the same time, to allay pain. Great relief was experienced while under the influence of the mercury before it affected the mouth; but when that became affected, a striking remission of pain and every other symptom was felt; the disease imperceptibly vanished, leaving the patient in a state of convalescence. Tonies were then resorted to, to restore the tone and strength of the system; and a perfect recovery took place. To have inserted the minutes of these cases would have taken up much more room than is consistent with the accustomed plan of your work. The grand query to which I would solicit attention is, whether the exhibition of mercury may not be attended with advantage in every inflammatory disease, upon this principle, that by affecting the system with it, and inducing a new action, you supersede the existing morbid one, and if not entirely destroy it, at least, in a great degree, mitigate, its effects? One caution it may be necessary to make, that its exhibition ought never to be entrusted to any but scientific enlightened men, who narrowly watch its effects, and are aware of the principle upon which it acts. Should these remarks tend in the least to excite an attention in the minds of medical men, to the subject in question, the end of the writer will be fully answered. I am, &c. July 25, 1810, VERAX. To the Editors of the Medical and Phyfical Journal. A GENTLEMEN, Correspondent having stated in your Journal for April, his Hints on Superfœtation, I beg leave to state the following case, that happened in my practice, for his observa tion. My patient was a young woman, but had had one child before; she was very correct in her reckoning, and went to her full time. As soon as I came to her I found her labour going on regularly; the membranes soon ruptured, and in the course of a few pains, a long shrivelled fœtus was expelled, which I then concealed until I had an opportu nity of examining it; the remainder of the labour went on very regularly, and was soon completed, by the birth of a fine large living child; the other appeared to me large enough for a six months foetus, but was scarcely any thing but skin and bone, and of a dark colour, though without fœtor or any signs of putrefaction; and what appeared to me most singular, was, there was no appearance of a funis attached to it, nor any placenta that appeared to belong to it. As the doctrine of conception has occasionally been discussed, allow me to insert the following case. I was called to a Lady at the Hot Wells, who, I was informed by the practitioner first in attendance, had been in labour forty-eight hours, and for the last twelve hours the child's head had been pushing against the hymen, which was yet unbroken; after a few hours more patient waiting it gave way, but I could not complete the labour without the use of the forceps at last; and afterwards I questioned the husband respecting the hymen, who described to me very accurately, that it was the same as when he first married, and that he never had been able to enter the vagina completely. St. Augustine's Place, Bristol, I am, &c. W. D. ROLFE. То |