Hunter the merit of having first ascertained, by experiment, that medicines retain their specific powers of action when introduced into the circulation. The following is the paragraph in which this claim is asserted:

'That medicines can be received into the circulation, and, as soon as they arrive there, produce their effects upon different parts of the body, is proved by experiments made by the late Mr. Hunter, although he had no idea of their being usually carried there before they produce the different actions so well known to follow their exhibition by the mouth. He found that infusions of the following substances, received into the circulation by the jugular vein, immediately produced the same effects which more slowly follow their being taken by the mouth. Infusion of opium brought on drowsiness. Infusion of ipecacuanha, vomiting. Jalap, vomiting and purging. Infusion of rhubarb, a profuse flow of urine. These effects ceased in a few hours, and appeared to have in no respect : injured the animal's health.'

It is not necessary to make any long comment on this representation, which every tyro in physiological science must know to be incorrect. One decisive reference will be quite sufficient, and we shall satisfy ourselves with quoting Haller's El. Phys. 1. 3. sect. 3. § 7. et seq.

On the cutting Diamond. By W. H. Wollaston, M.D. Sec. R.S. After having observed that no adequate explanation has been given of the remarkable power of the diamond in cutting glass, and that the conditions on which the effect depends had never been duly investigated, Dr. W. proceeds to give the result of his own examination. He learned, on inquiry, that the persons who prepare the instruments for glaziers always use naturally crystallized diamonds, technically called sparks; which, it seems, differ from artificially polished specimens in the circumstance of all the surfaces being curved, so that the meeting of any two of them presents a curvilinear edge.'. In order to effect the division of the glass, it is not necessary to penetrate the surface forcibly, by which means it would be bruized and fractured, while the clean cut required for the division would not be produced, but the intended cut must be tangent to the edge near its extremity. The reason why a clean cut is more effectual, than a fracture formed by forcibly urging the diamond against the glass, is that in the one case the force applied to break the glass is dispersed over a space of some extent, and may be diverted? from its course; in the other, the whole force is confined suc cessively to the mere points of a mathematical line, which may be conceived the bottom of the fissure, and is directed▸ onward by the facility with which the adhesion of each particle in succession yields to its progress.'

REV. MAY, 1817.

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An

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An Account of the Lasomery of a Man of nation Iran zz Brak. By A. F. Moray, Lag na Lener to Dr. Wal-Oisemattina and Experiments on the Mom of uttune bo fund a tot By W. H Walton, M.D. Sec. Rud. -These are very interesting and curious papers; the first aving a minute secount of the Cucovery of a mam of five ron, and an the ciroitustances respecting is a woman.co and physical characters: the latter containing exam of ita exmportion, in which the car will and dexterity of the analyst are diclated to mock atractare. It was dsowvered in the year 1-84. by an individual who was employed in attending came, and was observed by him to be totally different in ita nature from any of the neighbouring minerals; and, from the idea that it was metallic, and procesly contained the precious metals, an attempt was made to remove it, but without scrocess. Mr. Mornay found it still lying on the carriage on which it had been placed twenty-five years before, and had therefore an excellent opportunity of examining every part of it. He took a correct outline of its shape; and, with respect to its size and weight, he informs us that

• It is about seven feet long, four feet wide, and two feet in thickness, besides a sort of foot on which it now stands, of about six inches in height. The solid contents, however, cannot be inferred correctly from these dimensions, since the broad part is hollowed out underneath very considerably. After making due allowance for the cavities, I estimated, on the spot, the solid contents of the whole mass to be at least 28 cubic feet, which at 500lb. will make its weight to be 14,000lbs.'

The upper part is of a brownish black colour; the lower was covered with a ferruginous rust; and it has several cavities in it, some of which contained fragments of quartzose stones. Immediately under the outside coating, or rust, the mass exhibits a bright metallic appearance; it gives sparks when struck with a steel; it becomes luminous by friction; and it is magnetic.

We transcribe the very neat and ingenious mode which Dr. Wollaston adopted for detecting the nickel which this mass was suspected to contain.

Having filed from my specimen as much as I judged sufficient for my purpose, (which need not exceed of a grain,) I dissolved it in a drop of nitric acid, and then evaporated the solution to dryness. A drop or two of pure ammonia was then added to the dried residuum, and gently warmed upon it in order to dissolve any nickel that might be present. The transparent part of the fluid was then led by the end of a rod of glass to a small distance from the remaining oxide of iron, and the addition of triple prussiate of potash immediately detected the presence of nickel by the ap

pearance

pearance of a milky cloud, which was not discernible by the same means from a similar quantity of common wrought iron tried at the same time.'

Dr. W. afterward ascertained the absolute quantity of nickel, which he found to be four per cent.; while in the oxydated crust, taken from the spot on which the mass lay before it was removed, the quantity of nickel was only 3.06 per cent., in consequence of the additional weight which the alloy acquired by oxydation. The Doctor remarks that, from the presence of nickel in this mass, we cannot but regard it as having the same meteoric origin with the various other specimens that have before been found.'

On Ice found at the Bottom of Rivers. By T. A. Knight, Esq. F.R.S. Mr. Knight here gives an account of the facts which he observed on the subject in the river Teme in Herefordshire. After an intensely cold night, but when no ice was formed on the surface of the water,

The stones in the rocky bed of the river appeared to be covered over with frozen matter, which reflected a kind of silvery whiteness, and which, upon examination, I found to consist of numerous frozen spicula crossing each other in every direction, as in snow; but not having any where, except very near the shore, assumed the state of firm compact ice. The river was not, at this time, frozen over in any part; but the temperature of the water was obviously at the freezing point, for small pieces of ice had every where formed upon it in its more stagnant parts near the shores; and upon a mill-pond, just above the shallow streams, (in the bottom of which I had observed the ice,) I noticed millions of little frozen spicula floating upon the water. At the end of this mill-pond, the water fell over a low weir, and entered a narrow channel, where its course was obstructed by points of rock and large stones. By these, numerous eddies and gyrations were occasioned, which apparently drew the floating spicula under water; and I found the frozen matter to accumulate much more abundantly upon such parts of the stones as stood opposed to the current, where that was not very rapid, below the little falls, or very rapid parts of the river.'

Mr. K. conceives that the accumulation of spiculæ, which constituted the ice in the Teme, could not produce it in a slow stream; and that therefore, if ice be ever found in such situations, it must be derived from another source.

On the Action of detached Leaves of Plants. By the Same. -The object of this paper is to shew that a fluid, similar to true sap, actually descends through the leaf-stalks of plants; and thus to complete the author's hypothesis that the sap is elaborated, or acquires its specific properties, in the leaves. In order to prove this fact, portions of the bark of a vine

twig were detached from all communication, except with the leaf; and it was found that, under these circumstances, the bark increased in size. It was also discovered that the leaves of the potatoe, when planted in the earth, formed at their base a quantity of matter similar in its nature to the tuber of the plant, which must have been generated in the leaf, Experiments of a similar kind were tried with the leaves of mint; and it appeared that, when the leaves of a vine-branch were immersed in water, the shoot to which they belonged continued its growth. The exact course, by which the fluid thus elaborated is conveyed into the different parts of the plant, is not easily to be detected: but the author thinks that we can have no doubt of the actual passage of the sap from the mature to the young leaves and the fruit, because if the former be destroyed the growth of the latter immediately ceases.

On the Manufacture of the Sulphate of Magnesia at Monte della Guardia, near Genoa. By H. Holland, M.D. F.R.S.The place at which this manufacture is produced is about eight miles N.W. of Genoa, forming one of the highest points of the chain of the Appennines that lie contiguous to the coast. The mountain consists principally of primitive slate, with a mixture of marble and serpentine; and a considerable quantity of transition and secondary lime-stone, with some partial deposits of sand-stone and coal. Having described the aspect and general features of the district, the author informs us that the original object of the works was to procure copper and iron pyrites: but the formation of the crystals of sulphate of magnesia, during the process, gradually changed the views of the proprietors. The operation by which the salt is separated is this. The pyrites is roasted, and then exposed in heaps to the atmosphere, when small crystals of sulphate of magnesia effloresce on the surface. These are collected and lixiviated with water, and made to filtrate through alternate layers of sand and straw. The filtered fluid contains the sulphurets of iron and copper, as well as that of magnesia; and, to separate the latter, the milk of lime is added, which forms sulphate of lime, and subsides together with the oxyds of the metals. It is magnesian lime-stone which is employed for this purpose, as being supposed to afford a larger product than the common lime: but Dr. Holland doubts the reality of this alleged fact,

On the Formation of Fat in the Intestine of the Tadpole, and on the Use of the Yelk in the Formation of the Embryo in the Egg. By Sir Ev. Home, Bart. V.P.R.S.-We have here a detail of the progressive changes which the common tadpole experiences, until it becomes converted into a perfect frog; and

likewise

likewise of the corresponding changes in the state of the Surinam frog, the rana paradoxica. It is found that the intestines of the animals, in their state of tadpoles, contain no oil or fat, but that this substance appears when their metamorphosis is completed; and, as the intestinal canal of the tadpole is excessively long, Sir Everard concludes that such a deposit of fat is necessary to the metamorphosis of a tadpole into a frog, and that such unusual length of intestine is required to admit of so large a quantity of fat being formed in so short a time, and therefore that the intestine is the laboratory in which the fat is formed.'

From some comparative analyses by Mr. Hatchett and Mr. Brande, we learn that the yolk of the egg contains a quantity of oil, mixed with albumen, but that the spawn of frogs includes no oil. It is, however, conceived that the presence of oil is essential to the formation of perfect bone; so that those animals, whose ova are without this substance, must be supplied with some apparatus by which it can afterward be produced. Although the facts and observations in this paper are not without their value, we think that the train of reasoning employed is vague and inaccurate, and that the hypothesis brought forwards is not established.

On the Structure of the crystalline Lens in Fishes and Quadrupeds, as ascertained by its Action on polarized Light. By David Brewster, LL.D. F.R.S. London and Edinburgh.-It is observed by Dr. Brewster that no subject has been more frequently investigated than the structure and functions of the eye: yet he thinks that none has less repaid the pains that have been bestowed on it. We should be disposed to controvert this statement, were not we able to employ our time more usefully in relating the important facts which Dr. Brewster has himself ascertained on the question. By a train of well-directed experiments, in which he applied his former discoveries on the polarization of light to detect the structure of the crystalline, he was led to draw an accurate conclusion respecting this point. He plunged the lens into a hollow parallelopiped of glass, filled with Canada balsam, when he found a regular optical figure varying its shape during the revolution of the crystalline.' The optical appearances, that presented themselves by placing the body in different positions, are all carefully detailed; and, by comparing them with the effects produced on light by different bodies of a known consistence and structure, it is ascertained that the central nucleus and the external coat are in a state of dilatation, while the intermediate coats are in a state of contraction, and that these opposite states are not dependent upon each other as