the amount of sulphuric acid in the urine of several other persons was mainly dependent upon the amount of sulphur taken with their albuminous food; and that when farinaceous food, containing only a small amount of gluten, such as bread and butter, rice, and similar food, was taken, the amount of sulphuric acid in the urine fell. The same observation was made by Clare, in a series of experiments which he performed upon himself. During three days he lived on meat only, and at the end of those three days he had discharged the respective amounts of sulphuric acid as follows: on the first day, 2.094 grammes; on the second day, 5·130 grammes; on the third day, 3.868 grammes. He then, during two days, ate common mixed diet, and discharged, on the fourth day of the experiment, 3.592 grammes; and on the fifth, 2-262 grammes, of sulphuric acid. The next three days he restricted himself to vegetable diet, and discharged, on the sixth day of the experiment, 2.262 grammes; on the seventh, 1.394 grammes; on the eighth, 1022 grammes. On the ninth and tenth day he again took his ordinary diet, and secreted 1979 and 2.859 grammes of sulphuric acid on each day respectively. Table showing the influence of diet upon the amount of Sulphuric Acid discharged in the Urine (from Clare's experiments). SO,+HO. 2-094 5-130 3-868 3-59212-262 2-26211-39411-0221-9792-859 3 This table exhibits quite clearly that the influence of the meat diet showed itself on the second day of the experiment only, in which point the observation differs from that of Vogel, in which the rise in the quantity of sulphuric acid took place already during the night and on the morning following the meat supper. However, this later appearance of the increase is compensated for by its lasting so much longer, that the urine of the fourth day, being the first of the ordinary mixed diet, is yet under the influence of the meat diet of the previous day, the first day of vegetable diet is yet under the influence of the previous day of mixed diet, and the diminution of the sulphuric acid by the vegetable diet lasts yet over the whole ninth day, when ordinary diet was already taken. We have now sketched the circumstances on which the amount of sulphuric acid in the urine is ordinarily dependent. There may, however, be accidental causes which increase the sulphuric acid, and as these must be assigned the internal use of sulphur, sulphurets, sulphuric acid, and sulphates. The internal use of sulphur has been found by Krause' to increase the amount of sulphuric acid in the urine. It was observed by Boecker and Clare that large doses of red sulphuret of antimony caused a rise in the amount of sulphuric acid in the urine. The action of the sulphuretted mineral waters, which is generally ascribed to the formation of sulphuric acid in the body, forms an interesting subject for inquiry in this direction. As to sulphuric acid, it was observed by Vogel that it increased, in the urine of a patient who had taken it for the cure of hæmoptoe, from 12 to 3.0 and 3.28 grammes. Gruner made some observations regarding the influence of sulphates, and found that sulphate of soda, when taken internally, caused a considerable increase in the amount of sulphuric acid in the urine. In one experiment the hourly quantity rose from 0.049 grammes to 0·122, 0·176, 0·145, and 0.220 grammes. In another experiment the rise was equally well marked, namely, from 0.041 grammes to 0.138, 0·122, and 0.164 grammes. The time required by the organism to discharge the excess of sulphuric acid varied in different experiments. The influences which different physiological conditions of the body may have upon the amount of sulphuric acid in the urine it has not yet been possible to ascertain. We do not know whether the organism requires a certain amount of the sulphates, below which secretion cannot be carried on, or whether sulphates may be retained and accumulated in the economy. The influences of rest and activity, and of the ingestion of large quantities of water into the stomach, did not appear materially to affect the amount of sulphuric acid in the urine, according to some experiments of Clare and Gruner. Vogel, however, believes it probable that such influences exist, that the secretory activity for sulphuric acid is dependent upon certain individual and cosmic influences; a conclusion to which we are led by the fact that different persons oxydize and discharge (supposing it to be discharged as soon as formed) the sulphur taken with their albuminous food with different degrees of rapidity, and that the secretion 'Krause, A., De transitu Sulfuris in Urinam,' Dorpati, 1855. of sulphates in any form in some is spread over a longer period of time than in others. Vogel, also, from observation, is of opinion that the prolonged use of sulphates in digestive doses is decidedly weakening, and believes it probable that this depressing action may be due to an accumulation of the salts in the system. When to this it is added that sulphate of soda in larger doses is an emetic and sulphate of potash a poison, the question into the influence of sulphuric acid and sulphates in the urine becomes one of sufficient importance to fix the attention of future inquirers. Quantity of Sulphuric Acid in disease. The observations hitherto made on this point have not yielded any very decided result. Vogel found sulphuric acid considerably diminished in most acute febrile diseases. As patients suffering from these diseases take little food, and that little mostly of a vegetable nature, the diminution is partly accounted for. The same observer found, however, exceptions to his general rule, in three patients affected with violent pneumonia. In these cases the amount of sulphuric acid discharged was considerably above the normal average. The first patient, who was treated with large doses of digitalis, secreted the following quantities of sulphuric acid on nine respective days: 24, 31, 29, 5·7, 43, 1.8, 1.1, 1.6, 2.7 grammes. Of the two other cases, which took a rapidly fatal turn, the first showed the amount of sulphuric acid to be 2.9 and 14 grammes on two respective days, the other on the day of decease 44 grammes. On contrasting these figures with those obtained in cases where the amount of sulphuric acid is less, the difference becomes very striking. In a man with diphtheritis buccalis Vogel_found only 05 grammes of sulphuric acid for the day. In a patient with febrile catarrh it was 0.29 and 0.38 grammes. A man affected with pleuritis secreted 0.63 grammes. A girl suffering from rheumatic fever discharged 0.8 grammes at the height of the disease, another with erysipelas of the face 0:48 grammes. In chronic diseases Vogel found the amount of sulphuric acid to be variable, but mostly below the normal average; and it remained so in cases where the secretion of chlorides could be vastly increased by administering diuretics, as in cases of dropsy. An increase in the amount of sulphuric acid discharged by patients affected with chronic disease could only be observed after the ingestion into the stomach of sulphuric acid and sulphates, and in diabetic patients after a liberal meal of meat. Thus a patient labouring under icterus secreted 1.4 grammes of sulphuric acid; a case of rheumatism of the neck gave 111; a case of emphysema of the lungs, 12 grammes. A case of amenorrhoea showed 0.5; of fluor albus, 0.7; of habitual hypermenorrhoea, 0·97 and 1·1 grammes. A dropsical patient who, under the influence of diuretics, secreted 33 grammes of chlorine during twenty-four hours, discharged only 1 gramme of sulphuric acid during the same time; and on the day following, with 28 grammes of chlorine, only 0.5 grammes of sulphuric acid. A patient, who took sulphuric acid internally, secreted more than 30 grammes of it during twenty-four hours, and a patient affected with diabetes insipidus discharged 5.2 grammes. Pathological indications. If there can be no doubt about the origin of sulphuric acid, the determination of its quantity in the urine must be useful for determining the amount of disintegration of albuminous matters in the system, in cases where the ingestion of sulphur in any form or combination is very low or altogether suspended. The amount of sulphuric acid would then, perhaps, correspond in a certain degree with the amount of urea, supposing their inclination to pass the kidneys to be equally great. But upon this point there are yet doubts. Where we find both urea and sulphuric acid in increased quantities, we may be sure that it is due to the oxydation of a large quantity of animal matter introduced into the stomach, to animal or meat diet. A considerable diminution of the quantity of sulphuric acid, on the other hand, indicates that the patient has been taking little or no animal food, little or no vegetable food, or no food at all. Of course, all these features may be constant or accidental. A sudden rise in the amount of sulphuric acid, but of short duration, would, under all circumstances, have to be referred to the ingestion of sulphur in some of its combinations, organic or inorganic. The relations of sulphuric acid to the processes of the animal economy are by no means simple. Introduced in an organic combination, sulphur becomes oxydized, and in the form of the acid has to join a base. It would, of course, deprive another base of its acid by the right of the stronger. The neutral phosphates are thus most probably deprived of some part of their base. Sulphuric acid or sulphates are not present in the juices of flesh, as was first ascertained by Berzelius, and afterwards confirmed by Liebig. For the precipitate which baryta causes in the juice is, in many cases, entirely soluble in nitric acid; and if a precipitate of sulphate of baryta remain undissolved, its quantity is so small, that it cannot be determined by analysis, even from so large a quantity of flesh as that of an entire fowl or an entire fox. The analyses of the quantity of sulphuric acid in the blood will have to be repeated without incineration, which, as we have seen, destroys the relative proportions of acids and bases in the salts of the alkalies. The production of sulphuric acid then being apparently confined to the blood, it becomes a question of high importance, whether the action of the kidneys does not in part consist in the final oxydation or that stage of disintegration of albuminous matter, in which sulphur, in the form of sulphuric acid, leaves the organic combination, joins a base, and appears in the urine. This influence of sulphuric acid (the produce of the oxydation of the sulphur in albuminous substances) in producing in part the acid reaction of urine was first pointed out by Liebig.2 Albumen contains 1.6 per cent. of sulphur and 0.4 per cent. of phosphorus.3 White of eggs contains more sulphur than albumen from blood. Casein contains 0.84 per cent. of sulphur. We may trust soon to know all intermediate stages of matter from albumen down to urea and sulphuric acid, when the analysis of these substances in the urine will be of still greater value than even at present we anticipate. 1 Chem. Unters. über das Fleisch,' p. 76. 2 Ann. d. Chem. und Pharm.,' 1. p. 181, et seq. |