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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 drowsi

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. I. 3. sect. 3. § 7. et seq.

On the cutting Diamond. By W. H. Wollaston, M.D. See. 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 elean 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 sucu cessively to the mere points of a mathematical line, which is may be conceived the bottom of the fissure, and is directed onward by the facility with which the adhesion of each partiele in succession yields to its progress.” Rev. May, 1817.

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I: eyesente art=26b7an isitizo va acoged 1. 2. 2 200 was comerred to be us cinert is te bay of the sea beras; ast, ka the was that it was the and process coctaita se pred sreta. an asteapt was made to remove it, Det bort woh Mr. Mornay found it sure 1200 the carriage on which it iz tken pissed twenty-Ere tears before, ac, bora tiverte an exce..ect opportany of exabing etery prart of it. He took a correct Guinne of is shape; and, with 1**t to its size and weighi, he iniurns as that

• It is about even feet long, fou feet wide, and two feet in thickness, besides a sort of foot on which it Dow stands, of about uit inches in height. The sound contents, however, cannot be inferred correct.y from these dimensions, since the broad part is hoiiowed out underneath very considerab.y. After making due allowance for the cavities, I estimated, on the spot, the solid conunta of the whole mars to be at least 28 cubic feet, which at soolb. will make its weight to be 14,ccclbs.'

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 stonen. Immediately under the outside coating, or rust, the man 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 man was suspected to contain.

' Having filed from my specimen as much as I judged sufficient for my purpone, (which need not exceed too of a grain,) I diswolved it in a drop of nitric acid, and then evaporated the solution w 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

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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

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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 enploy 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

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