Parts of the Urinary Passages; and on the Effects that are produced upon them by the internal Use of solvent Medicines, from Mr. Wm. Brande to Everard Home, Esq. F.R.S.-In this paper Mr. Brande attempts to trace the calculus at its first formation in the kidney, and to examine the changes which it undergoes in the urinary passages. A large collec tion of calculi in the Hunterian museum (in which the greater part of the specimens have histories of cures annexed to them) has given him an opportunity of undertaking the investigation on a considerable scale of extent, and therefore we think much confidence may be put in his conclusions. The calculi formed in the kidneys consist of pure uric acid and animal matter. The proportion of the animal matter is sometimes large, amounting to more than of the calculus, at other times nearly the whole is uric acid. If the calculus has fallen into the infundibula. or pelvis of the kidney, its composition has sometimes proved to be the same; but at others the external laminæ are composed of the ammoniaco-magnesian phosphate and phosphate of lime. Of the calculi found in the bladder, but a small number are composed of uric acid. Mr. Brande gives the following statement of the composition of different calculi found in the bladder. In operating on the uric calculi from the bladder in some instances there was a far more considerable loss in attempt. ing to obtain their pure uric acid than in the kidney calculi, Mr. Brande has discovered that this loss was occasioned by the presence of urea. He extracted this substance, from the calculi of the bladder both by water and alcohol. One of these calculi by an attentive analysis gave the following result: Urea and muriate of ammonia Grains. 5.2 6 48.8 60 Mr. B. from these circumstances is inclined to believe that urate of ammonia as an ingredient of the calculus, has no existence. The evolution of ammonia depends probably on the decomposition of ammoniacal salts. The mulberry calculi, in which oxalate of lime predominates, contains also uric acid and phosphate of lime in considerable proportion. Four distinct substances,' says Mr. Brande, are extremely rare in calculi; I have seen one in which the uric acid, the ammoniaco-magnesia phosphate, the phosphate of lime, and the oxalate of lime, were all perfectly separate and distinct layers.' The calculi formed upon extraneous substances for their nuclei have no uric acid in their composition. Mr. Brande has examined only two or three specimens of calculi of the urethra. Their composition appears to be the same as that of the calculi of the bladder. He concludes the analytical part of his paper with the analysis of calculi from other animals. We cannot enter into the minutiae of this part of the inquiry. We must content ourselves with saying that none of the specimens contained uric acid : most of them had a portion of carbonate of lime, which is not found in human calculi, and the other ingredients were phosphate of lime, and the triple ammoniaco-magnesian phos phate. These facts on the whole make it probable that the uric acid is secreted by the kidney, and that the other materials are deposited from the urine. The solvents employed against calculous complaints are of two kinds; alkalies and acids. Alkalies when pure dissolve the uric acid: but it is very uncertain whether they have this effect on the body, since the carbonates have no such power, and the urine contains carbonic acid enough to deprive the alkalies of their causti.. city. But it is acutely remarked by Mr. Brande, that if alkaline medioines prevent the deposition of uric acid they favour that of phosphate of lime and the triple phosphate, These substances are retained in solution by the carbonic. acid and phosphoric acid of the urine; and by saturating these the substances held in solution are precipitated.Though therefore the uric sediment diminishes, and may disappear, the gravelly or calculous matter, is only altered in its composition. Upon the same principles, lime-water, forming insoluble compounds, must be really hurtful. It has been proposed, when the calculous matter consists of phosphates, to use acid solvents, particularly muriatic acid. 'Even then,' says Mr. B. the nucleus of uric acid would remain, and thus a great deal of time would be lost without any permanent advantage.' This objection has little validity. A small stone must at least be better than a large one; and how is this time to be better employed? If, indeed, as Mr. Brande asserts, uric acid re-appears, and even seems augmented in quantity, it deserves serious consideration. But before we give our assent to this assertion, it must be proved by sufficient experiments. XVI. Some Observations on Mr. Brande's Paper on Calculi. By Everard Home, Esq. F.R.S.-Mr. Home has recorded in this paper some curious examples of deception with regard to the supposed solvent power of alkaline medicines. Two patients who had been great sufferers from symptoms of stone, having arrived at the age of 68 or thereabouts, become free from their pains. The one had used the saline draught in the state of effervescence, and to this medicine the cure was attributed. After death, twenty calculi were found in the bladder; and the cessation of the symptoms proved to be owing to an enlargement of the prostate, which made a barrier between the calculi and the orifice of the bladder. The second patient was under a course of Perry's lixivium. Fourteen calculi were found in the bladder; and the cessation of the symptoms proved to be owing to exactly the same cause. Both these cases had been published as proofs that the stone had been dissolved. In several cases calculi bave been found in cysts, formed be tween the fascicoli at the muscular coat of the bladder, so as to be entirely excluded from the general cavity, and therefore they had caused no uneasiness. Two, three, and even four such cysts have been found,each containing a calculus of the size of a walnut, XVII. On the Changes produced in the atmospheric Air, and Oxygen Gas by Respiration. By W. Allen, Esq. F.R.S. and W. H. Pepys, Esq. F.R.S.—The delicate and important process of respiration has exercised the ingenuity of the chemical physiologists more than any other of the operations which are perpetually carrying on in that stupendous natu ral laboratory, the animal system. The delicacy and the extreme accuracy of the experiments necessary to arrive at stable conclusions, and the difficulty of constructing an unexceptionable apparatus, have prevented our attaining to certainty on questions, with regard to which certainty does. not appear, from the nature of things, to be out of our reach. We hope that the present memoir will dissipate much of the doubt and obscurity which have clouded a curious and interesting point of physiology. The apparatus used by these zealous colleagues in difficult researches is simple enough. One large water gasometer, capable of holding four thousand two hundred cubic inches of gas, contained the air to be inspired. Two other gasometers, filled with mercury, received successively the air expired. Proper stop-cocks regulated the successive parts of the process; and it was conveyed into jars standing in a mercurial bath for the purpose of analysis. We need not enter more into details; it would indeed be difficult to do so unassisted by a diagram. In the first ten experiments which were made, the loss sustained by the air, after having passed through the lungs, proved to be much smaller than from the reports of other experimenters they had been prepared to expect. Some allowance is to be made for the resistance given by the machinery to a complete expiration. There seems also a remarkable discordancy in some of the trials. The deficiency in one experiment we find marked at 4 inches, and in another at 62, upon nearly equal quantities of air. The first object of inquiry was into the changes produced in the air by natural inspiration. In one experiment 26.55 cubic inches of carbonic acid were given off per minute. But the quantity is variable in different subjects. In another person as much carbonic acid was given off in 5 minutes, as in the former experiment in 11 minutes and it appears that whenever atmospheric air is taken into the Jungs it returns charged with about 8 per cent. carbonic acid. The faster respiration is performed, the more carbonic acid is given off, and consequently the more oxygen is consumed. In an experiment with a very large quantity of atmospheric air 32 cubic inches of carbonic acid were given off per minute, and its proportion to the whole was exactly 8 per cent. There is one obvious source of deception in experiments of this nature performed upon a small scale. The air contained in the fauces, in the trachea, and perhaps in the Jarger branches of the bronchia,is in a great measure returned unaltered. Hence, in a single expiration, the proportion of carbonic acid is smaller in portions first expired than in the last portions. The first portion contains only from three to five per cent. carbonic acid, while that which is expelled from the lungs by forcible expiration contains 9.5 per cent. Our experimenters next proceeded to examine into the effect of making the same portion of air pass repeatedly through the lungs. The result was rather unexpected. First, there was but a very small addition of carbonic acid: 100 parts of the respired air contained but 9.5.of acid, whilst after ordinary respiration it contains 8 or 8.5. The remaining gases were 5.5 oxygen, and 85. azote. Now, reckoning the whole oxygen (that which is separate and that contained in the carbonic acid) there appears in this experiment a loss of 6 per cent. of the oxygen, and an increase of the azote. It was first suspected that some gas, as the gaseous oxide of carbon, or carbonated hydrogen might have been given off from the lungs. But this suspicion proved groundless. Hyper-oxygenized muriatic acid, mixed with the oxide of carbon, converts it in twenty-four hours into carbonic acid, But no such effect was produced upon the expired air. There is therefore when the same air is repeatedly passed through the lungs a loss of about 6 per cent. (out of the whole air) of oxygen. This is very remarkable, as in ordinary respiration no such loss can be detected. It appears that 5363.55 grains, or about 11 ounces troy of solid carbon are emitted by the lungs in the course of twentyfour hours; aud that 39534 cubic inches of oxygen gas are consumed in the same time. In natural respiration, a sinaller quantity of air can come into contact with those parts of the lungs calculated to act upon it. It is probable, therefore, that less carbonic acid is given off; but at all events, the quantity is very considerable. They now proceeded to ascertain the effects produced upon oxygen gas by respiration. The water gasometer was filled with oxygen which contained only 2.5 per cent. of azote. The inspiration of the gas raised the pulse in ten minutes from 72 to 88: the operator felt a general glow over the body to the very extremities, with a gentle perspiration; this, however, went off in a few minutes, and no remarkable deviation from the ordinary state was experienced. In this experiment a greater quantity of cartonic acid was formed from oxygen than from common air; the propor tion was little more than three to two; and it is inferred that one use of azete is to regulate the quantity of oxygen, which shall be taken up in the act of respiration. More than hundred cubic inches of azote were added to the gas by the |