Through the observations of Winter, Mosler, and Vogel, it has been established that the rise and fall in the hourly amount of phosphoric acid is a regular one during each twenty-four hours, the rise invariably taking place soon after the principal meal of the day, which was taken at noon. The maximum secretion was observed during the hours of the evening; the quantity fell during the night, and was at the lowest ebb during the morning. These fluctuations are well illustrated by the following table given by Vogel. Table showing the amount of Phosphoric Acid secreted by four individuals during one hour of the night, afternoon, and forenoon. This table shows that different persons discharge the phosphorus taken with their food at different periods after the ingestion, some more quickly, others more slowly; in some the process is spread over a longer period of time than in others. Thus B. discharged the greater part of the phosphorus taken with his dinner soon after it; the secretion of phosphoric acid reached its climax in the afternoon, and fell during the night and following morning until the next principal meal. The difference between the hours before the meal and after it is here greatest. In C. the climax of the secretion falls more towards the evening, and there is less difference between afternoon and night. In D. the maximum hourly average is in the night; and probably his digestion was much slower than that of the other three persons, though all four took their dinners at one and the same time, namely, 1 p.m. Physiology of Phosphoric Acid in the Urine. The evidence regarding this point, which may be obtained by analysis of the urine, is very similar to that given con cerning sulphuric acid. The introduction into the body of phosphorus, either in the form of the acid, or of phosphates, or in combination with albuminous substances, gives rise to an increase of the acid in the urine. Total abstinence from food, or from food containing phosphorus, on the other hand, diminishes the amount of phosphoric acid in the urine. Total abstinence will, however, not cause the entire disappearance from the urine of phosphates, as has been observed with regard to chloride of sodium. This is, perhaps, partly due to the continued oxidation of albuminous substances. Of these positions proof is afforded in the following facts. Aubert observed the urine of a person to contain 2.8 grammes per day under ordinary circumstances. This person took 31 grammes of phosphate of soda, whereupon the amount of phosphoric acid in the urine rose to 41 grammes for twentyfour hours. When abstaining from food, Mosler found phosphoric acid to sink to half the ordinary quantity; when he took large meals of albuminous substances, the amount of the acid became doubled in consequence. This But the excretion of phosphoric acid is not exclusively dependent upon the quantities introduced. A series of observations demonstrate that the same influences which govern the excretion of chlorine and sulphuric acid, are active in the excretion of phosphoric acid. Different degrees or morbid changes of the secretory activity of the kidneys, actual disease of the kidneys, changes in the mode of disintegration of matter in the organism, must be looked to as causes of the variation of the amount of phosphoric acid. The varying influence of individual structure or individual disposition has been illustrated by Vogel's table. observer states, moreover, that the drinking of large quantities of water causes an increase in the amount of phosphoric acid beyond the quantity introduced with the water, which can only be explained by an increased production in the body of phosphoric acid, by changes which make an increased amount of phosphates available for excretion, and by a stimulated activity of the kidneys. The organism may at one time contain an excess of phosphoric acid, at other times the acid may be deficient. It will, however, be difficult fully to establish these points, until the normal amount of phosphoric acid contained in all parts of the body and its changes and variations within the range of perfect health be known. And then the examinations will have to comprise a complete analysis of all food, and of all excretions. We cannot do better than draw the reader's attention to the chapter on the inorganic constituents of the juices of flesh, p. 75 of Professor Liebig's 'Researches on Flesh' (respective meat). The remarkable facts there revealed throw much light on the physiology of phosphoric acid and its salts, on its relation to other component parts of the body, to other salts, to food, digestion, assimilation, to the formation of blood, its function, and depuration. These experiments, to use the words of the author, "however incomplete they may be, may serve as starting-points for future researches." Quantity of Phosphoric Acid in the Urine of disease. The results regarding this point obtained by Professor Vogel from more than a thousand examinations are, in the following sentences, given without any comment. In acute but not very severe diseases, the amount of phosphoric acid in the urine decreases at first most probably in consequence of the low diet, and afterwards rises again with a more liberal allowance of food. During convalescence the normal amount is sometimes exceeded, in consequence of an increased quantity of food. If the illness, though combined with violent fever, only lasts a short time, the decrease of the amount of phosphoric acid is sometimes very slight and scarcely perceptible. EXAMPLES. Males.-1. A young man, affected by severe febrile angina tonsillaris, discharged 2.8 grammes of phosphoric acid on the day of his reception into the hospital. He had an emetic given to him, which caused violent vomiting. This was followed by low diet. On the second day the amount of phosphoric acid had fallen to 17 grammes. He now improved, and had quarter diet. The two following days showed 2-6 and 2.5 grammes of phosphoric acid respectively. He now was placed upon half diet; and on the following day, the PO, rose to 3.2 grammes. He recovered and was discharged. 2. Pneumonia, not very severe. The patient was discharged after eight days. The daily amounts of PO, were 2.4, 2.5, 2.9, 2.4, and 2-3 grammes. 3. Pneumonia, more severe. During the acme of the disease the daily amounts of phosphoric acid were 1·7, 0·8, 2·1, 1.2, 0.9, 2.1, 19, 11 grammes. 4. Pneumonia, similarly severe, 16, 14, 22, 23, 16 grammes. 5. Febrile bronchial catarrh, 14, 15, 17, 1.5, 2.8 grammes. 6. Convalescence from severe pneumonia, 38, 27, 3.2, 3.5 grammes; 3·9, 1·8, 2·5, &c. 7. Similar case, 1.9, 5.6, 2.8, 1.5, 3.2, 2.8 grammes. 8. Convalescence from severe bronchial catarrh, 4.8 grammes. 9. Catarrh of the organs of digestion, with eczema and violent fever. The case took a rapid course, so that the patient was dismissed cured after eight days. The amount of PO, was 2-3, 2·6, 2·7, 2·6, 3.4 grammes. Females.-1. Rheumatic fever, 2.1, 2.3, 2.2 grammes. When the diseases are of a more severe nature, so as to cause a long abstinence from food, or to take a fatal turn, the decrease of phosphoric acid in the urine becomes much more considerable. Thus a girl with severe febrile catarrh of the lungs discharged, during the acme of the disease, 07, 0.5 grammes of phosphoric acid; during convalescence it rose to 13 and 2.5 grammes. Fatal end of acute tuberculosis of lungs, 04, 0.4, 0.3, 0.3, 0.2, 0.1, 0.08 grammes (day of decease). Gangrene of the lungs, fatal issue, 30, 25, 2·20, 0·7 grammes. In some exceptional cases the amount of phosphoric acid discharged during the height of acute diseases, may considerably exceed the amount discharged during health. A man of middle age suffered of pneumonia, and was treated with large doses of digitalis, cured and discharged, 4.3, 5.1, 4.1, 8.4, 7.9, 4.5, 2.9, 5.0 grammes. In chronic diseases the excretion of phosphoric acid takes a very irregular course, and though remaining mostly below |