testine in some conditions of disease, and which Sir E. asserts are in all respects similar to ambergris; and the formation of concretions, consisting of oil and animal mucus, in a case of severe stomach affection, which was considered as originating in the irritation of biliary calculi, and for which pretty considerable quantities of olive oil were taken by the patient.

This fact appears as a communication from Dr Babington, as does also another of pure animal fat being discharged from the intestines of a child of three years old, at intervals of ten or fourteen days, and in the quantity of several ounces at each period. In addition to this evidence, Sir E. brings forward the result of experiments which were instituted with a view to obtain a farther confirmation of his opinion. An attempt was made to procure fat from the contents of the colon in different parts of its course, but without success; the contents of the lower intestine of a duck, the evacuations of which had been suspended for seven days, were next examined, but no fat was procured, except from a portion of the contents of the cœcum which was macerated in a dilute solution of nitric acid. Portions of muscular fibre were digested in bile, both of the human subject and the ox At the temperature of 100°, some fatty matter was formed upon the surface, and the fecal odour was perceived on the fourth day. No fat was formed at the tempera ure of 60°, and in one of the experiments at 100°, in which the putre ac ion process was rather advanced, no traces of fat could be detected. A small film of fatty matter was obtained by macerating a fecal evacuation which had been passed after a constipation of six days. And finally, the case of a child is adduced, which lived several months but without growth, and without any fat being deposited under the skin, and in which, after death, the gall bladder was found to be wanting, nor was there any duct from the liver to the intestinal canal.

Sir Everard thinks that all this affords a sufficient_body of evidence in proof of his opinion, that the formation of animal fat takes place in the large intestines. In our judgement the evidence appears to be singularly defective, and the conclusion, hasty and unphilosophical. To say nothing of the obvious importance of great extent of the large intestines, to those animals which may be supposed to be unfavourably situated in regard to the abundant supply of food, as affording an extensive surface for the absorbents;in what way we would ask can the formation of concretions, from the combination of oil taken into the stomach with

the mucus of the intestinal canal, afford either direct or indirect evidence of the conversion of the alimentary matter in the large intestines into fat? Or what analogy can there be between the conversion of dead animal muscle into fat, by a process which takes place at a low temperature, and is so slow as to require years for its completion, and any change which can take place in the alimentary canal of a living animal, in which the food is urged forward with so much rapidity, when the functions are properly performed, as to pass through the whole length of the intestines in a few hours, perhaps twenty-four at the utmost.

As to the conclusions drawn from the experiments which Sir E. caused to be made, they appear to us to be very far from being correct and satisfactory deductions, for we cannot find that the results exhibited that regularity and uniformity which are necessary to justify so positive a conclusion. But even supposing we were authorized to draw this inference with respect to the changes which alimentary matter, derived from the animal kingdom, might undergo, what proofs or examples have we of this conversion having been effected out of the body on vegetable matter? And would not the difficulty remain as great as ever consequently with respect to animals subsisting wholly on vegetable food? Sir E. remarks that this theory recommended itself to his adoption the more strongly, because there is no other mode with which he is acquainted, by which animal fat can be formed. We are far from thinking that he has proved it to be formed in this way in the animal body, and we would ask what greater difficulty there can be in referring its formation to the general process of secretion, than that of bone, or muscle, or than the bile, the saliva, or any other of the secreted fluids, except that in the one case we can see the apparatus by which the function is performed, and in the other we cannot, for the means by which the function is performed, is, in both cases equally unknown to us.

XXII. On the Colouring Matter of the Black Bronchial Glands, and of the Black Spots of the Lungs. By George Pearson, M. D. F. R. S.

The colour of the Lungs undergoes a remarkable change in the human subject in the progress from infancy to age, but the fact though too obvious to have been at any time overlooked, has not been examined in reference to its immediate cause. This object has been attempted by Dr. Pearson in the present communication, which bears the appearance of considerable labour having been expended in the investigation.

By subjecting detached bronchial glands, or portions of the substance of the lungs, which were thickly studded with black points or congeries of lines, to the action of caustic potash in solution, or the more active acids, such as the nitric,or muriatic acids, the organized animal substance was dissolved, and a black powder was obtained, to which the colour of the part was owing, and which, being insoluble, subsided to the bottom of the vessel. This black powder, when subjected to the action of the nitrat, or oxymuriate of potash, deflagrated as charcoal does, and afforded carbonic acid. When heated alone, it burned with the odour of animal matter, and afforded a portion of animal empyreumatic oil, and there was also a production of hydro-carbonate gas, and a trace of prussic acid. Dr. P. therefore concludes, that this colouring matter is an uncombined animal charcoal, or, as he expresses it, not existing as a constituent ingredient of organized ani'mal solids or fluids.' With respect to its origin he appears to us to have adopted a theory which is neither very ingenjous, nor much in correspondence to any physiological view of the functions of these important organs. He thinks it is introduced with the air which we breathe, and that it is consequently absorbed from the air cells, by the vessels which open upon their surface.

This is a very mechanical view of the subject, and if it were the real source, we should naturally expect to find the change of colour gradually going on from the commencement of life to its close, which is contrary to our experience of its progress. We have observed it in a very high degree in comparatively young subjects who have fallen victims to consumption. Besides, when we consider that the pulmonary Iorgans are the great outlets by which carbon is thrown out of the system, such an opinion seems hardly reconcileable with their known structure and purposes in the animal economy. It appears more probable that it takes place as a consequence of the function of the lungs being less perfectly performed, either as the effect of disease, or of that gradual change which, though not disease, is connected with the less vigorous performance of all the functions, which is a condition of advancing life. An inquiry into the relative proportions of carbonic acid given out at different periods of life, might throw some light upon it. We should have supposed that the notion of the oxygen of the air passing through the coats of the air cells and into the pulmonary vessels, was exploded since the publication of Mr. Ellis's ingenious and able inquiry, if Dr. P. had not brought it forward on this occasion, as a support to his theory. The fact

noticed by Dr. P. that the colouring matter is not removable by ablution, nor by maceration in water, is, we think, adverse to the idea of its being simply an extraneous matter, taken up by the absorbents.

XXIII. Experiments on the Alcohol of Sulphur, or Sulphuret of Carbon. By J. Berzelius, M. D. F. R. S. Professor of Chemistry at Stockholm; and Alexander Marcet, M. D. F.R S. One of the Physicians to Guy's Hospital.

This able and elaborate paper is arranged under four divisions, the first of which relates to the preparation and general properties of this singular compound; the second details experiments made to determine whether hydrogen is one of its constituent principles; the third refers to the presence of carbon; and the fourth, to the proportion of its elements.

The preparation was conducted on the plan recommended by Clement and Desormes, viz. by volatilizing sulphur, through charcoal heated to redness in a porcelain tube, and condensing the product in water. The fluid thus obtained is of a pale yellow colour, extremely volatile, and producing a great degree of cold during its evaporation, and depositing in a crystalline form sulphur which is held in solution. To procure it perfectly pure it is necessary to distil it at a temperature not exceeding 110°. It is perfectly transparent and colourless, with a pungent taste and fetid smell. It boils under the ordinary atmospheric pressure at between 105° and 110. and does not congeal at the temperature of 60° below zero. It is highly inflammable, burns with a blue flame, and emits copious fumes of sulphureous acid. It is readily soluble in alcohol and ether, and is precipitated from its solution in alcohol, by the addition of water. It is not soluble in water. It combines readily and perfectly with either the fixed or the volatile oils, and dissolves camphor rapidly. No action is exhibited with potassium when in the liquid state, but in the gaseous form, the potassium becomes ignited, and emits a reddish flame, and a black film is deposited upon its surface. When water is introduced, a greenish solution is obtained, having the properties of sulphuret of potash, and in which some carbonaceous matter is suspended. It has no action on mercury, or on the amalgam of silver or of lead. The alkalis dissolve it, but none of the acids except the nitro-muriatic, and the oxymuriatic gas in a humid state, have any action upon it. It combines with the new detonating compound lately described by Sir H. Davy, and the compound formed by their union does not explode when heated to ignition, nor does it exhibit any action when brought into

contact with olive oil. It also prevents the detonation of the compound when brought into contact with phosphorus, but if the quantity of the detonating compound predominates, the mixture inflames.

The experiments which were to determine the question of hydrogen being contained in this liquid as one of its constituent parts, were made with oxygen, oxymuriatic gas, muriate of silver heated to redness, and different metallic oxides strongly heated, through which it was passed in a state of vapour, and the results were such as to afford sufficient proof, that no hydrogen entered into its composition.

The experiments instituted for the purpose of ascertaining if carbon was contained in it, as one of its essential component parts, were perfectly decisive in their results. The gaseous matter, produced by its combustion in very pure oxygen gas, was found to be a mixture of sulphureous acid gas, of carbonic acid gas, and of gaseous oxide of carbon; and when it was combined with the solutions of lime and barytes in water, carbonic acid was slowly formed, and occasioned a "precipitation of the earths from the solutions. The determination of the proportions in which the sulphur and the carbon are combined in this body, was attended with some difficulty; but its perfect decomposition was ultimately effected, by slowly passing it in a state of vapour through the red oxide of iron coarsely pulverized. By a very careful analysis conducted in this manner, it was ascertained to contain 84. 83 parts of sulphur and 15. 17 of carbon in the 100. or 100 sulphur and 17. 89 carbon. These proportions

correspond so nearly to numbers which, on Dalton's prin-ciple, represent these substances respectively, that there can be no reasonable doubt of the truth of the conclusion which these excellent chemists have drawn, that it consister two atoms of sulphur united to one of carbon.

There is an Appendix to this communication by Professor Berzelius, which exhibits the characteristic proofs of his profound knowledge of chemical science. It relates to several points connected with the subject of the paper, or arising out of it.

The Professor first relates the details of the mode which was pursued to ascertain the elementary proportions of the compound; he then compares these results with the deductions obtained by the application of the law of definite proportions, and offers some general observations on the atomic theory.

The remaining portion is occupied with an account of some new combinations of the sulphuret of carbon with the alkalies;