Vierordt's Calculation.

Ingesta and Egesta of an healthy adult man.

Ingesta in 24 hours (in grammes).1

(The O and H of the starch are taken as water.)

It will be observed that Vierordt does not assign any salts to the perspiration, but includes them all in the urine and fæces; the sulphur and phosphorus are also not distinguished, nor does he assign any nitrogen to the skin.

I Any of these amounts, multiplied by 15-44, will give the amount in grains.

Professor Fick's table is taken from Hildersheim: 1

Ingesta in 24 hours, in grammes, for men of from 50 to 60 kilogrammes weight.

Total

2903-793 269-909 7-248 18-094 630-9467-618 3:483 25-232 4-411

In addition to the H and O of the starch which are taken as water, 131 grammes of water are presumed to be formed in the system. The qualities of the water and of the H and O in the columns of ingesta and egesta do not, therefore, correspond in the two tables.

1 Hildesheim, Die Normaldiät, Berlin, 1856. For much fuller details on this subject, and on the relation of the food to the excretions, I beg to refer to Hildesheim's masterly work.

CHAPTER I.

ON THE VARIATIONS IN THE URINARY EXCRETION DURING HEALTH, FROM PHYSIOLOGICAL CONDITIONS.

THE composition of the urine varies greatly in different individuals, and in the same individual from day to day, owing to the unequal influence of varying physiological conditions. It is no easy matter to assign to each of these conditions its exact influence, and all that can be at present attempted is an enumeration of them, and an approximative estimate of their several effects.

SECTION I.

SEX.

Excretion of urine in adult women.-Becquerel has stated that women excrete more urinary water, but less solid matter, than men, but this is incorrect. Some women may pass more water and more solids than some men, but (if weight be disregarded), as a rule, females excrete both less urinary water and solids than the other sex.

The urine has not been so carefully analysed in women as in men. Placing together the observations of Becquerel,1 Lecanu,2 Bischoff, Mosler, Beigel, and Ranke," the following table gives the mean of numerous analyses in twenty adult women, between sixteen and forty years of age.7

1 Traité de Chimie path., 1854, p. 278.

2 Simon's Chemistry, by Day, vol. ii, p. 165; and Journal de Pharmacie, 1839,

t. 25.

3 Die Harnstoff als Maass der Stoffwechsels, 1852.

4 Beitrage zur Kenntniss der Urin-absonderung, Giessen, 1853; and Archiv für wissenschaft. Heilk., Band iii, p. 410, et seq.

5 Unters. über die Harn., &c. Aus Nova Acta, &c., Band xxv, besonders abge. druckt, p. 20, et seq.

Ausscheidung der Harnsaure, p. 7.

7 In an "adult woman" (exact age and weight not given), Warnecke found the mean of seven days to be 26-8 grammes, or 414 grains, on mixed diet (quoted by Moore, Dublin Medical Press, July, 1859). As the age is uncertain, I have not inuded it.

Urine of adult women in twenty-four hours.

The mean amount of urea in different women may vary from 12 to 30 grammes, but it is usually from 16 to 28.

The excess of the phosphoric acid over the mean amount in adult men, probably merely arises from the analyses in which phosphoric acid is given being too few in women, so that the mean amount is placed at a higher figure than it will be when the analyses are more numerous.

The excretion of urea, according to weight, cannot be given at present with any certainty, but the following are the principal facts known:

1 Virchow's Archiv, 1859, Band xvi, p. 211. The chloride of sodium in this woman amounted to no less than 25 grammes (=386 grains) in twenty-four hours, in consequence of a very salt, rich diet.

2 Archiv für wiss. Heilk., Band iv, p. 500.

If the mean weight (55 kilogrammes, or 121 lbs. avoird.) be considered the same in the case of the other ingredients, we obtain the following table:

It would, then, seem probable (though it is certainly not proved) that women excrete, according to weight, a little less urea than men (1 kilogramme in women = 0.414; in men = 0-459 gramme, or 0-500; p. 24, Introduction). Professor Lehmann' and others have already stated that the amount of urea to weight is less in women than in men, an opinion based on Valentin's figures.

The range of urea in different women appears to be quite as great as in men (from 0.600 to 0-320 gramme per kilogramme, in twenty-four hours).

The other ingredients are excreted in ratio to weight in very nearly the same proportion as in men; the slight excess of phosphoric acid is probably owing to the analyses in women being few in number, so that the amount is too high.

The deviation in women from the mean amount is as great as in men. Many women secrete on an average only 12, 14, or 18 grammes of urea daily; others 28 to 30. The usual individual range appears to be about 4 or 5 grammes above and below the mean amount proper to the person.

No satisfactory experiments have as yet been made on the effect of sex at different ages; the few facts known are included in the next section.

SECTION II.

AGE.

Fatus.-The urine of the fœtus is either slightly acid or neutral; it is destitute of urea2 and is highly albuminous, and sometimes

1 Handbuch der Phys. Chem., 1859.

Moore, Heller's Pathology of the Urine, 1855, p. 32; and Dublin Quarterly Med. Journ., 1855, vol. xx, p. 88.