Imágenes de páginas
PDF
EPUB

with respect to their conftitution and method of living, who are most liable to this disease, and thews its remote or predisposing causes from meteorological observations. Led by these previous discussions and observations to the knowledge of the original feat of the difurder, and the matter that properly constitutes its he maintains, that the former is the membrana adiposa or cellu. Jar fubstance, and the latter, the mucus of that membrane re. duced to a state of diffolution, while the principal diffolvent of this mucus is a matier emitted by insensible perspiration, which had long been retained in the small cells of the mucous membrane. This hypothesis is supported by clinical observations and numerous practical facts. It is also by such facts that our Author proves the real existence of an ESSENTIAL miliary fever, while he indicates the characteristics which diftinguish it from the other exanthematous fevers. Finally, he lhews, that in its principle it belongs to the catarrh, and that in its commencement and progress, it is inlammatory and putrid.

Mem. VI. Concerning a Preservative against coniagious epidemio cal Difcafes. By M. CARRERE. This is not a new discovery, but tne revival of an old one, the merit and importance of which are confirmed by new examples, and judicions observations. It has often been observed in epidemical disorders, that persons who had an habitual running or discharge, either natural or artificial, were prele: ved from the contagion. Our Author was the physician of a family in which eleven persons were seized with an epidemical disease; the father alone, who had an ulcer in his leg, in a state of abundant fuppuration, escaped the infection. A mulritude of finilar cases are mentioned in this me. moir, on the authority of the most respectable teftimonies. These have induced M. CARRERE to recommend, as equally effcctual, a draining a periure, formed by a blistering plaifter, a cautery, or a secon, which may be more especially necessary to those who are obliged to attend or approach the persons that labour under epidemical disorders. During a plague in the empire of Morocco, whici, in the space of five weeks, carried off 85,000 pessons, a Jew physician, who took care of the sick, and many others, were saved from the contagion by the means of cauteries or issues.

Mem. VII. C- Inoculation. By Dr. GIROD - Mem. VIII. Concerning fome Abufes that have been introduced into the Practice of Ing ulation, and ihe Precuutions that are necessary in order to render this Operation as falutary and advantageous as possible. By M. DE Horne. We join together these two memoirs, though they are separated by intervening ones in the volume before us. In the fir, M. GIROD relates the success of his pradice in this important branch of his profesion. In the small town of Millau in Rouerge, between the 20th of March and the 2015 of June,

229

he canomie chelling Obrigting

229 persons (from the age of 8 months to 19 years) were inoculated without the loss of one; while, at the same time, of 234 persons, who were attacked by the small-pox in the natural way, 32 died in the disorder, and several others fell victims to its fatal consequences. Among many interesting observations contained in this memoir, we cannot omit the mention of one which does peculiar honour to the candour and frankness of our Author. He observes, that those who had been inoculated by the common people, without any preparation or medical attend. ance, went through the disorder with more success than those who were under the care of regular physicians. This recals to our remembrance the old proverb-that too much cookery spoils the broth; but whatever truth and wisdom there may be in this maxim, we would prefer a soup made by a cook before that which came from the hands of an oftler, ceteris paribus.

The abuses in the practice of inoculation, that are reprobated in the second memoir, are, If, the attempts to diminish the number of puftules by the use of mysterious remedies to enervate the force of the virus, and by diverting its course from the skin in order to convey it through the redum :- 2dly, A want of attention to the choice of a proper temperature of the air, equally re. moved from violent heat and intense cold.-3dly, An indiscri. minate application of this practice to persons of all ages and conftitutions.- 4thly, The use of a variolous matter for the infertion of the fmall-pox, taken, without distinction, from persons of a sound or vitiated constitution.-5thly, The insertion of too great a quantity of the virus.-6thly, The neglect of a ju. dicious preparation of the body, with several other abuses, for which we refer the reader to this judicious and instructive memoir.

Mem. IX. Concerning the purgative Remedies that are good for Sheep. By M. DAUBENTON. This curious memoir is well adapted to correct an error which has hitherto prevailed in the treatment of domestic animals. It has been thought sufficient to proportion the doses of the remedies, that are employed in the disorders of the human species, to the size of animals, without examining by proper experiments, whether these remedies opesale on different kinds of animals in the same manner as they do on the human body. Experience and observation have convinced M. DaubENTON that they do not ; that there is a great diverfity in their effects; and that there are remedies which operate powerfully on men, and, nevertheless, produce no sensible effect upon animals. This consideration excited him to undertake a series of experiments in order to ascertain the effects of several remedies for theep, and more especially purgativesa These are enumerated here, and accompanied with observations

and and reflections, which will prove highly inftru&ive and useful to the proprietors and inspectors of the fleecy fock. but have never been able to accomplish a union of the wax with the other ingredients. By caufticaring the alkali we readily obtained a perfect solution of the wax; and we suspect that the kali alhes used by our Author had been newly burnt, and on that account were in some degree cauftic.

Mem. X. Observations on the different Metbods of administering Electricity, and the Effects they have produced. By M. MAUDUYT. This piece, which, on account of its merit and importance, bas been published separately by order of government, is a supplement to two memoirs on medical electricity publilhed in a preceding volume. It is designed to exhibit a full and collected view of all the different methods of administering electricity, and all the diseases to which it has been applied, with more, or less, or no, success. It contains little new to an EngliQ reader, as it is, for the moft part, an abridgment, though a very judicious one, of M. CAVALLo's Elay on the Theory and Practice of medical Electricity, published in 1780, and of Dr. WILKINSON's Latin differtations, published at Edinburgh in 1783.

Mem. XI. Reflexions on the Effects of virriolic Ether and nitrous Ether in the animal Oeconomy. By M. LAVOISIER. Those who make use of ether, either as a calmer, or as a remedy for head-achs arising from bad digestion, will find useful instruction in this memoir, with respect to its operation, and the method of administering it.

ART. XXXI. Della Pittura, &c. i.e. A Memoir concerning Eucaustic Painting with Wax. By M. J. M. Astori, Honorary Member of the

Academy of Painting at Venice. 8vo. 1786. M UCH learned labour has been employed to ascertain the UV method used by the ancients in their encauflic painting, The various attempts that have been made to recover this me. thod, by Count Caylus, Messrs. Bachelier, Muntz, the Chevalier Lorgna, the Abbé Requeno, and other virtuosos, are well known. Whether this ancient art has been so recovered, as it was formally practised, is still doubtful. But methods that come near to Pliny's ambiguous description of it, have been ingeniously contrived and carried into execution with remarkable success; and M. Muntz, among others, has proposed several ingenious improvements in the art of encaustic painting. M. ASTORI comes last, though not the least, in this series of improvers and inventors. He observes, that the ancients thickened their colours with wax, and this they had the art of keeping constantly in a state of Auidity, which no modern attempts, says he, have been able to effect without the presence of fire. His method of producing this permanent fluidity, is fimilar to that mentioned in our fixty-fifth volume, p. 95; with which process we were favoured by a gentleman well versed in the art of painting,

He keeps kali, or soda, in maceration, for a considerable time, in a quantity of cold water, sufficient to cover it, so that the water

may

may become saturated with the falts of the kali. To prepare the wax, he melts it in a small pot, and, before it boils, he pours upon it the water of the kali, filtrated through grey paper, having previoully infused into the water between 8 and 10 drops of the best Spanish honey. He agitates this mixture over a fire, until all the ingredients are perfectly diffolved and blended together. He then puts the wax into a vessel, where it remains in a ftate of softness, like that of liquid pomatum, and fit for use. The liquidity of this mixture may be augmented by diluting is with warm water. After this part of the process is finished, the colours, mixed up with water, are diluted in the water of gum arabic, in a quancity proportioned to that of the wax. The wax-composition is also diluted apart, and afterward the whole is mixed up together, and blended and incorporated into one liquid body. When mineral colours are employed, the wax must constitute one half of the mixture, a fourth when lac is used, and a third when any other colours are preferred.

Before the colours are drawn upon the canvass, it must be rubbed over with white-lead, gum arabic, and water of war; this latter is a water, in which wax, prepared in the manner above mentioned, is diffolved. When the picture is finilhed, it muft be washed over with the wax water, repeatedly poured along its surface; and after being wiped, it is to be placed ncar a gentle heat, fufficient only to make the wax emit a little smoke ; and this warmth will make the colours rise from the canvass with a more vivid lustre. When the picture is grown cool, it is to be rubbed with a cloth, co render its surface smooth and shining.

Our Author observes, that his wax water may be employed as an excellent varnish to preserve prints, which are exposed in frames, from the noxious impresions of the air; and he indicates the manner of using it for this purpose. He also thinks that it may be usefully employed for the preservation of pictures drawn with oil colours, and also of crayons. He has not yet finished all his plans for the improvement of colouring, that important branch of the art of painting, which has suffered so much by the destructive influence of time: he is fill going on with his expe. t'iments, and he has attempted a combination of the oil of pop. pies with wax. With this mixture he proposes to finish a piece, which, with respect to the duration and beauty of its colours, will unite all the advantages of ancient and modern painting.

Such is the account of this work which we have received from one of our foreign correspondents; the original we have not yet been able to procure. The reader will observe a deficiency in the description of the process ; though the particular quantity of the honey is mentioned, the proporcions of the other ingredients are not specified. We have tried various proportions,

but

[ocr errors]

AR T. XXXII. Kongl. Vetenskaps Academiens Handlinger, i. e. Memoirs of the Royal

Academy of Sciences at Stockholm for the Year 1781. W E shall now proceed to give a more particular account of

the principal articles in these memoirs, the general contents of which we barely announced in the Appendix to our goth volume, p. 570.

Mem. I. Concerning the constituent Parts of the Tungsten. By M. CHARLES WM. Scheele. The constituent parts of this kind of iron are little known. · Cronstedt calls it ferrum calcio forme, terra quadam incognita intime mixtum. That on which the experiments here related were made was taken from the mine of Bitzberg, and was of a pearl colour. - We cannot circumstantially relate all the experiments made on this metal by the learned Academician, without going beyond the bounds which a multitude of other articles prelcribe to this. We shall therefore content ourselves with indicating their results. M. Scheele observes, that fire made no remarkable change in the tungsten, and that neither glass of borax nor boiling water act upon it. The solution of it by spirit of nitre, when precipitated by alkali of tartar, furniches a wbite precipitate, of an acid kind, which is soluble in boiling water, in the proportion, however, of twenty parts of water to one of the precipitate. It gives a red hue to the dye of lacmus, and is acid to the tafte. .

Several experiments were made to ascertain the nature of this acid. Being dried and exposed to flame by a tube, it contracted a brownish yellow hue, became afterwards brown, finally black, and neither produced smoke, nor exhibited any indication of fufion. Being combined with borax it was changed into a blue glass, and, tried with microcosmic salt, into sea-green glass. It Joses gradually this colour when it is presented to the point of a flame : a small quantity of nitre removes the colour immediately : but it returns when the blue part of the flame is directed to the ore; whence it appears that the colour is revivified by the phlogiston of the flame. When the acid of tungfien has been pulverised and brought into ebullition with a small quantity of the spirit of salt or nitre, the powder becomes yellow, and, with spirit of vitriol, contracts a blue colour. When it is dissolved in water and saturated with alkali of tartar, it furnishes a neutral salt in very small crystals. When it is combined with volatile alkali and fal ammoniac, it appears under the form of small

points

« AnteriorContinuar »