the estimate of Kirwan,* nearly 144'04 cubic inches, and 100 grs. of oxymuriatic gas, as appears from Mr. Dalton's experiments,† are equal to 137.9 inches, which, being reduced, give a proportional bulk, as 100 of hydrogen to 95.7 of oxymuriatic gas. Thus we see that Mr. Dalton's experiments agree almost exactly with the result of calculation; and if the hydrogen he employed was contaminated by the slighest admixture of extraneous matter, the quantity of oxymuriatic gas condensed by it must of course have been proportionally lessened. Mr. Dalton, having denied the existence of aqueous vapour in muriatic acid gas, ascribes the appearance of hydrogen during the action of certain bodies on that gas to the decomposition of the acid, which he looks on as a quaternate compound of oxygen and hydrogen. While, however, he admits the fact as stated by Sir H. Davy, that "when potassium was heated in muriatic acid gas as dry as it could be obtained by common chemical means, the gas wholly disappeared, and from one-third to onefourth of its volume of hydrogen was evolved, and muriate of potash was formed." He questions the accuracy of an experiment detailed in the Bakerian lecture for 1809, by which this conclusion was established. In this experiment it was found that 8 grs. of potassium absorbed 22 cubic inches of muriatic acid gas, and gave out 8 inches of hydrogen. Before proceeding to examine Mr. Dalton's reasoning on this experiment, it may be well to take a view of it, unconnected with his speculations on the nature of muriatic acid. According to the analysis of Sir H. Davy, § 8 grs. of potassium may be converted into potash, by union with about 1.29152 gr. of oxygen. In order to furnish this oxygen, if water be its source, 1495934 gr. of that fluid must suffer decomposition; and this quantity is sufficient, at the rate of 25 per cent. to give the gaseous form to 5'983736 grs. or in the proportion of 26 26479 to 5.6459 grs. only of muriatic acid gas. At the same time that the oxygen of this water is absorbed by the potassium, its hydrogen, amounting to 204414 of a gr. or 7.82297 inches, must be set at liberty. Thus it appears that the hydrogen evolved was almost exactly equal in quantity to what could be afforded by a portion of water sufficient to oxidate the potassium employed. The experiment appears, however, to be inaccurate, with regard to the absorption of the 22 inches of muriatic acid gas: for 9.29152 grs. of potash are capable of combining with the real acid contained in 5·59055 grs. of muriatic acid gas, which Essay on Phlogiston, p. 30. + New System, p. 297. measure 9.641375 cubic inches only. And if we suppose that none of the acid condensed in consequence of the loss of its water entered into union with the potash, and that the acid thus employed carried all its water with it, we have only in addition to this quantity either 5.983736 grs, measuring 10-0062 inches, or 5.6459 grs. measuring 9-42625 inches, making in all a condensation of either 19-643675 or 19.067625 inches. But it is obviously more natural to suppose that the acid deprived of its elasticity from the loss of its water afterwards entered into union with the potash: in which case the results of the experiment should have been 13.76396 grs. of muriate of potash, an evolution of 7.82297 inches of hydrogen, a condensation of 1.328152 gr. of an-hydrous muriatic acid, and not less than 11.9977 cubic inches of residual muriatic acid gas. It will be seen by a reference to page 290 of Mr. Dalton's work, that he infers by calculation that during the oxydation of a quantity of potassium sufficient when in the state of potash to unite with 22 inches of muriatic acid gas, were water the source of the oxygen, nearly 16 inches of hydrogen would be evolved; while if the acid gas suffered decomposition 8 inches would appear. This, however, is not perfectly accurate: for the quantity of real acid contained in 22 inches of the gas is capable of combining with 23.0872 grs. of potash, and, for the formation of this, 2-8175 grs. of oxygen are requisite. Now this quantity of oxygen is, in the state of water, combined with not less than 18.0444 inches of hydrogen. On the other hand, if Mr. Dalton's view of the nature and constitution of muriatic acid be correct, and if this body were the source of the oxygen, there should have been an evolution of 6.0148 inches only, from the oxydation of 20-2607 grs. of potassium. If, however, the 22 inches of muriatic acid gas were the sole source of the oxygen, 16.917 grs. only of potassium would have been required; and the evo lution of hydrogen could not have exceeded 4·3739 inches. As, however, the quantity of oxygen required by 8 grs. of potassium is almost exactly sufficient to form water with 8 cubic inches of hydrogen, and as it is certain that 9.29152 grs. of potash cannot form muriate of potash by union with the real acid of 22 cubic inches of muriatic acid gas, is it not better to argue upon a foundation in some degree known, and from phenomena consistent among themselves, than to build speculations on a part of an experiment, which is almost demonstrably impossible? In the only other experiment of this sort detailed by Sir H. Davy, 5 grs. of potassium took nearly 14 inches of muriatic acid gas, and gave about 5 inches of hydrogen: 5 grs. of potassium may unite with 8072 of a grain of oxygen; which in the state of water hold in union ·13505 of a grain, or 5·115 VOL. II. N° I. B inches of hydrogen. Now 94225 of a grain of water are capable of giving the gaseous form to either 3.769 grs. (measuring 6.3027 inches) or 3.55609 grs. (measuring 5.94664 inches) of muriatic acid gas; and 5.8072 grs. of potash can unite with the real acid contained in 2.9045 grs. or 4.857 inches of muriatic acid gas: so that the condensation could at most amount to only either 11:1577, or 10.80364 inches. If the condensations were not independent of each other, the results ought to have been 87117 grs. of muriate of potash, 5.115 inches of hydrogen, 8645 of a grain of an-hydrous muriatic acid, and 7.6973 inches of residual muriatic acid gas. Mr. Dalton has, in a subsequent part of his work,* joined with the French chemists in supposing potassium to be a hydruret of potash. He does not, however, look back to the reasoning in page 290, to inquire whether, from the action of potassium on muriatic acid gas, so much hydrogen be evolved, as might, besides the quantity ascribed to the conversion of the potassium into potash, leave a surplus to be accounted for from the decomposition of the acid. It is probable that there is not: and this probability will the better appear, if, for an instant, we admit the truth of Mr. Dalton's atomic theory. In every binate compound, the weights of the combined elements are proportional to those of their atoms. Mir. Dalton has stated the weight of the atom of hydrogen at 1, and that of potash at 42; of course, that of hydruret of potash must be 43. The amount of the hydrogen evolved in Sir H. Davy's first experiment, should therefore have been of 8 grs. or 1860465 of a grain; a quantity less than that noted by Sir H. Davy, by 0183675 of a grain, or about 702 of a cubic inch; and falling short of the result of calculation on the data of the experiment, by only •52477 of a cubic inch. It is almost superfluous to say that this slight discrepancy is not to be wondered at, in an investigation which is as yet only in its infancy. Mr. Dalton, however, says that water is a binate compound; therefore if 8 grs. of potassium contain as many particles as 204414 of a grain of hydrogen, and if the number of particles in this be equal to that contained in 1.29152 gr. of oxygen, it follows that, in these quantities of oxygen and of potassium, there exists an equal number of particles, and potash may be still an oxide of potassium. The hydrogen which appeared may of course have come entirely from the water, without any decomposition of the acid.† *Pages 484-486. + I would not be understood as having any reference here to Mr. Murray's views of the nature of potassium; but merely as arguing against its being a hydruret of potash. (To be continued.) ARTICLE VI. General Views of the Composition of Animal Fluids. By J. Berzelius, M.D. Professor of Chemistry in the College of Medicine at Stockholm.* HAVING related to my friend Dr. Marcet some observations that I have made on the subject of animal chemistry, and being invited by him to communicate them to the Medical and Chirurgical Society, I shall, in compliance with his wish, venture to submit to the Society some of the principal results that I have obtained at different periods, prior to my visit to this country, respecting the fluids of animals. Most of these observations have been published in a more unconnected state in different works in the Swedish language; but as they have not been translated into any other language, and as they have appeared to those who have seen them, to contain some new views, I am induced to offer them to the Society, in the hope that they will be received with indulgence. I. Of the Blood. In most of the analytical researches on blood, that of the bullock has been made the subject of experiment. I shall therefore begin with the analysis of the blood of that animal, and afterwards notice the essential points in which I have found it to differ from the human. A. Bullock's Blood. Blood may be regarded as a liquid holding a colouring matter suspended in it, but not dissolved. The first step in the process of accurate analysis should therefore be to separate the suspended matter by filtration. But this method succeeds only to a certain degree, and requires a time so considerable, that the blood undergoes spontaneous changes of composition before the sepation can be completed: for notwithstanding all possible care, the colouring matter will either pass through with the fluid portion, or by adhering in masses, prevent all farther percolation. Another mode is that of allowing it to subside by rest: but this also goes on with extreme slowness: the clear supernatant liquor loses its red colour but very gradually; and the colourless portion is not capable of being collected alone. The usual way of obtaining them separate is to take advantage of the coagulation * From the third volume of the Medico-Chirurgical Transactions, lately published. In my Forelasningar i Djurkemien, 2 vol. Stockh. 1808. And also in Afhandlingar i Fysik, Kemi, och Mineralogie, 3 vol. Stockh. 1810. of the blood, during which the fibrin enveloping the colouring substance presses out the serum. This method is indeed but very imperfect, as a large portion of the serum still remains attached to the red globules in the coagulum; but it is the only one that we can employ. I shall first consider the crassamentum, and its two constituent parts, fibrin and colouring matter. The Chemical Properties of Fibrin. Fibrin is insoluble in cold water. In boiling water it curls up, and after the ebullition has continued some hours, the water acquires a milky hue, but no gaseous product appears. By this operation fibrin undergoes a species of decomposition; the water in which it is boiled affords, by the addition of tannin, a precipitate of white and distinct flocculi, which do not cohere together by the heat, as those produced by gelatin. The evaporated liquid does not gelatinize to whatever degree it may be concentrated, and leaves a white, dry, hard, and friable residue, which is soluble in cold water, and has an agreeable taste similar to fresh broth, and totally unlike the salt and acrid flavour of the extract from muscles. Fibrin, by long boiling in water, loses its property of softening and dissolving in acetic acid. 2. In alcohol of specific gravity 0.81 fibrin undergoes a species of decomposition, and forms an adipocirous matter, soluble in alcohol, and precipitated by the addition of water; having often a very strong and unpleasant odour. The alcoholic solution leaves on evaporation a fat residue, which did not pre-exist in the fibrin, and which, as we shall find, is likewise formed by the action of alcohol on the colouring matter and on the albumen. Fibrin heated in alcohol retains its property of softening and dissolving in acetic acid. 3. By the action of ether fibrin is converted into an adipoeirous mass similar to the preceding, but in much greater abundance, and having a much stronger and more disagreeable odour. We are on this account precluded from employing generally either alcohol or ether in analytical experiments on animal substances. 4. In concentrated acetic acid fibrin becomes immediately soft, transparent, and with the assistance of heat is converted into a tremulous jelly. By adding water and warming it, this jelly is completely dissolved, with the evolution of a small quan tity of azotic gas. The solution is colourless, of a mawkish and slightly acid taste. During its evaporation a transparent membrane appears on the surface, and after a certain degree of approximation, the gelatinous substance is again re-produced: but this gelatine has no resemblance to that formed by paste. When completely desiccated it is a transparent mass which |