In properly discriminated cases of fever, with great increase of vascular action, and inflammatory determination to particular organs, what doubt can remain of the propriety of blood-letting, proportioned in degree to the peculiarities of individual instances. But by too much generalization and too little attention to the phenomena of individual cases, the phlebotomists and anti-phlebotomists have each fallen into important and alarming errors. The rational practitioner is guided in the management of any case by the peculiarities of that case, independent of hypothesis. A nice knowledge of the quality of the deviations from the actions of health, can alone direct in the choice and application of remedies. A predilection for venesection induces one party to call for more blood on all occasions; while the other, equally wedded to the notion of preventing debility, generally rejects or employs it in too trifling a manner to be useful. If the former mistake because they do not reason, the latter fall into error against reason. The most thoughtless empiricism has not gone further than the first, and the second, by supporting the increased morbid action, actually plunge their patients into the hazardous debility they labor to avoid. The rapidity with which the patient recovered his strength, on the removal of the febrile action," says the writer of this paper," notwithstanding those large evacuations, was, for a long time, matter of astonishment to me." In all instances of indirect debility, moderating the increased morbid action, reduces in the same ratio the chance of subsequent weakness. This axiom the reasoners have lost sight of, when they fear to use the means of reducing increased action on the apprehension of future debility. (To be continued.) MEDICAL AND PHILOSOPHICAL INTELLIGENCE. ROYAL SOCIETY.-On Thursday, May the 27th, a paper by Mr. Cater was read, comparing the Cassegrenian and Gregorian telescopes. These telescopes have been hitherto considered as quite similar. Mr. Cater was led to compare them in consequence of telescopes of both kinds being constructed by a self-taught artist at Ipswich, who has acquired the art of constructing both in remarkable perfection. The result of the comparison was, that the Cassegrenian telescope gave a much clearer and better defined image of the object than the Gregorian. Mr. Cater endeavours to account for this difference, by supposing that in the Gregorian telescope the particles of light interfere, and impede one another; while this does not happen in the Cassegrenian. On On Thursday, June the 3d, part of a paper by Mr. Brande was read, containing additional facts and observations on the use of magnesia in cases of urinary calculus. The paper was divided into two sections. In the first, Mr. Brande related several cases, in which the deposition of uric acid in urine and the accompanying symptoms were removed by the use of magnesia. Among others, a Gentleman of fifty-five was afflicted with pain in the kidney; a calculus at last passed into the bladder, and was voided by the urethra: it consisted of uric acid. His urine deposited a considerable quantity of red sand (uric acid). He tried alkalies, but they disagreed with his stomach. He was induced, in order to alleviate the symptoms of indigestion, to take a tea-spoonful of magnesia daily. His symptoms were gradually removed, and the urine ceased to deposit red sand. Several similar cases were given, in all of which the deposit of uric acid was put an end to by the use of magnesia. But in one case, after a certain time, the symptoms were aggravated, and a white sediment was deposited. This turned out, on examination, to be a mixture of phosphate of lime and phosphate of magnesia-and-ammonia. The object of the second section of the paper was to give an account of the treatment in such cases. Acids were administered, and different kinds were tried. Carbonic acid in the form of soda-water, citric acid, vinegar, cyder, oranges, lemonade, and muriatic acid, were tried in succession. The muriatic acid seemed to have answered worst. The other acids, in several cases related, removed the symptoms without inducing a deposition of uric acid. On Thursday, the 17th June, Mr. Brande's paper was concluded, Another case was related, in which the deposition of the phosphates in the urine was put a stop to by the use of carbonic acid, produced by mixing lemon juice and carbonate of potash, and drinking the mixture while in a state of effervescence. From these cases Mr. Brande concludes, 1. That when the alkalies, from any circumstance, cannot be used to put a stop to the deposition of uric acid in the urine, then magnesia may be employed with advantage. 2. That the deposition of the phosphates may be put a stop to by the use of mineral acids. 3. That the vegetable acids produce a similar effect, and that they. may be employed in much greater quantity, without injuring the digestive organs. On the same evening a paper was read by Mr. Axlay, of Bristol, on the phenomena of electricity. He began by stating what he considered as his peculiar theory of electricity; but which does not appear to differ from that of Cavendish, unless the fourth proposition be considered as peculiar. The theory consisted of the following propositions.- 1. A fluid exists called the electric fluid. 2. It is attracted by all matter, with a force inversely as some power of the distance. 3. Its particles repel each other. Hence it is elastic and compressible. 4. Electrics have a stronger affinity for it than non-electrics. No. 175. k k On On Thursday, June the 24th, a paper by Sir Everard Home, Bart. was read, containing additional observations on the squalus maximus, or great shark. Two of these fishes were caught at Brighton last December, and one of them was brought to London. It was particularly examined by Sir Everard and Mr. Clift, and this paper stated the result of the new observations. The figure given by Sir Everard along with his former paper is correct, except that a fin between the anus and tail is wanting. The liver is very tender, and consists of six lobes. The gall duct is dilated at the extremity which enters the intestines, the object of which seems to be to prevent the bile from returning into the liver. There is no gall bladder. The heart is very powerfully muscular, and there is a particular muscle connected with the valves, which Sir Everard conceives intended to impel the blood more powerfully through the gills when the animal is at a great depth under water; for the pressure of the water will, in that case, impede the circulation in the gills. It occurred to Sir Everard that this impeded circulation might be compensated by water at great depths containing more oxygen gas in solution than near the surface; but water being taken up from the bottom of a deep well, and examined, was found to contafn no more than water at the surface. It may be remarked here, that this trial was scarcely of such a nature as to be decisive. Well water, however deep, is nothing else than rain water which has made its way through the earth to the bottom of the well; and all of it having been equally exposed to the air when falling in the state of rain, ought to contain the same portion of air. The water examined ought to have been taken from the bottom of the sea; but it is not likely that any perceptible difference would have been found. Indeed, the experiment has been already made by Biot, who examined sea water taken up at the depth of 437 fathoms, and found the proportion of oxygen gas in it the same as at the surface. (Mem. d'Arcueil. i. 273.) But the swimming bladder being filled with oxygen gas in those fishes that live at great depths, this in all probability is intended to answer some such purpose. Sir Everard compared the heart of the squalus with that of several other animals. The squalus has no cerebrum, but only cerebellum. The cavity in which the semicircular canals of the ear is placed is uncommonly large. The lens of the eye is globular, and half sunk in the vitreous humour, which is very firm, and lodged, as usual, in separate cells. The retina is very thin. The cornea consists of three coats. Annals of Philosophy. Linna an Society. At the meetings of this Society on Tuesday the 1st, and Tuesday the 15th of June, a paper by Col. Hardwicke, on the bats in the British dominions in India, was read. He described and exhibited figures of 11 species, most of which inhabit trees, and live on fruits. The most remarkable of these is a very large species, having the aspect of a wolf, and of such a size that, from tip to tip, the wings extend 3 feet 8 inches. This species the Colonel considers either as the vampyre of Linnæus, or as nearly allied to it. It lives on fruits, and is considered by the Indians as quite harmless. The The Colonel found that it would eat raw flesh when hungry; but that it preferred fruits. The stories of its sucking the blood of living animals he considers as quite unfounded. The Society adjourned till the 2d of November. IMPERIAL INSTITUTE OF FRANCE. Account of the Labors of the French Institute for 1812. Botany and Vegetable Physiology.-Most physiologists have long admitted in plants an ascending sap, which mounts from the roots to the branches, and contributes to the increase of the branches in length; and a descending sap, which goes from the leaves to the roots, and to which some persons ascribe the chief part of the growth of the wood, and of course the increase of size in the trunk. M. Feburier, a cultivator at Versailles, has endeavored to collect these two saps separately. For this purpose he bored a deep hole in the trunk of a tree, and fixed a bladder upon the inferior surface, so as to prevent any liquid coming from the lower part of the tree from making its escape into this hole. He made another hole in the tree, and placed a bladder in the same way against the upper surface. He considered the sap collected in the lower bladder as the ascending sap, and that collected in the upper bladder as the descending sap. He gives many observations on the relative proportions of each in different circumstances. Wishing, in the next place, to determine the route which each of these saps takes in the inside of the tree, he plunged alternately by the two ends branches of trees in colored infusions. In both cases these infusions appeared to him to follow the woody fibres surrounding the pith. This induces him to ascribe the same route to both saps, in which respect he coincides with the result of other experiments made by Mustel. M. Feburier thinks, likewise, that the ascending sap contributes principally to the growth of the branches, the descending to that of the roots. But he thinks that the cambium, or that humor which transudes horizontally from the trunk, and which is looked upon as the matter which occasions the increase of the tree in thickness, proceeds, like the peculiar juices, from the mixture of the two saps. The presence of the leaves, necessary for the production of the descending sap, is of consequence also for the increase of the plant in thickness. But the buds, which M. du Pétite Thouars conceives to act so important a part in that operation, have nothing to do with it, in the opinion of M. Feburier; for it takes place, says he, as long as the leaves exist, and it ceases as soon as they are removed, whether the buds be left or not. As far as concerns the flowers and the fruits, M. Feburier assures us that he has observed the ascending sap, when it predominated, tending to determine the production of simple flowers, and the complete developement of the germs; that the descending sap, on the contrary, when too abundant, occasions the multiplication of flowers and petals, and the growth of the pericarp, and by consequence of the K k 2 fleshy fleshy part of the fruit; principles from which it would be easy to deduce many useful practices in gardening, and which explain various practices already pointed out by experience. According to M. Feburier, the alburnum deprived of its bark, but kept from the contact of the air, is capable of reproducing, by means of the cambium, the bark and epidermis necessary to cover it, as the bark produces constantly, even when partly separated from the trunk, liber and alburnum. In this point he has for antagonist our colleague M. Palisot de Beauvois, who has likewise employed himself in the investigation of these difficult questions, respecting the direction of the sap, and the formation of wood. According to this botanist, this escape of a glossy humor, which some physiologists suppose to proceed from the old alburnum, and to contribute to the formation of the liber, is not founded on convincing experiments. On the contrary, when a portion of bark is removed from a tree, and the wound is well rubbed, so as neither to leave liber nor cambium, neither the alburnum nor the wood produce any thing; but the edges of the bark gradually extend themselves, cover the naked wood, and produce liber and alburnum incontestibly proceeding from that bark. M. de Beauvois announces that he will soon elucidate this proposition at full length, which hitherto he has only noticed incidentally in his Dissertation on the Pith of Vegetables. The opinion of physiologists has been hitherto very much divided about the functions of the pith of vegetables. According to some, that organ is necessary to the life of plants during the whole of their existence according to others, it is only useful during the first years. of their life, or all the time that it is green and succulent, and may be easily confounded with the cellular texture. M. de Beauvois has made on this subject observations which tend to prove that the pith performs functions during the whole life of the plant, if not absolutely necessary to its existence, at least very important for its progress, and the growth of its branches, leaves, and especially of the organs neces sary for its reproduction. He has remarked that the circular layer, or fibres which immediately surround the pith, has always a form corresponding to the arrangement and disposition of the branches, twigs, and leaves: that in plants, with verticillated twigs and leaves, for example, the horizontal section of this case of the pith shows as many angles as there are twigs at each stage, and at each verticilla. In like manner, the medullary case of the laurel rose presents an equilateral triangle, if the branch below the verticilla has three twigs and three leaves; but if we cut it under the lower verticilla, where one of the twigs and leaves is usually wanting, it has only two angles, and the vestige of a third. This law is constant, even in herbaceous plants. M. de Beauvois has begun similar observations on plants, with opposite, alternate, dichotomous, spiral, and pinnated leaves. He expects to find them in the same relation between the medullary case, and the disposition of the branches, twigs, and leaves. For example, opposite leaves seem to require a round medullary case, becoming |