Beale 1

has affirmed that it causes the appearance of sugar. could not detect any sugar when chloroform was used; Dr. Bence Jones found only a trace after the employment of chloroform for twenty-four hours. Dr. Harley,3 in some experiments on rabbits with ether and chloroform, could detect no sugar in most cases; but in one experiment, after the animal had been rendered insensible five times in twelve hours, by a mixture of ether and chloroform, there was "a small quantity of sugar."

It would appear that a small quantity of sugar occasionally appears after inhalation of chloroform and ether.

3. Iodine, when inhaled, appears in the urine. Its effects on the urinary ingredients are not known.

4. The effect of smoking tobacco on the urine has been investigated by Hammond, who found that the amount of urine, of the urea, and of the chlorine, was lessened; the uric, phosphoric, and sulphuric acids, and the free acidity, were increased. The pulmonary carbonic acid was not lessened. Hammond refers the increase of sulphuric and phosphoric acids to increased metamorphosis of the nervous tissues, and the lessening of the urea to diminution in the metamorphosis of the nitrogenous tissues generally. This explanation may perhaps be doubted. The sulphuric acid is only in a small degree the representative of nervous tissue; and, in fact, we generally find its amount tolerably closely corresponding with that of the urea: what should cause a difference in the case of tobacco-smoking, is not clear. Hammond's experiments were continued over periods of ten days; but the other physiological conditions are not fully stated, and, in particular, the amount of food is not given with sufficient care.

5. The effects of other gaseous substances have not been properly examined. Professor Vogel has observed that arseniuretted hydrogen, when inhaled into the lungs, produces a most peculiar condition of the urine, which becomes black from dissolved blood pigment, and highly albuminous. Vogel conjectures that this is owing to rapid destruction of the blood-cells.

1 Brit. and For. Med.-Chir. Rev., Jan., 1853, p. 106.

2 Ibid., p. 109.

3 Ibid., July, 1857, p. 193.

4 American Journal of Medical Science, Oct., 1856.

Eine eigenthumliche Veränderung des Urins, Archiv des Vereins, Band i, p. 209. The same effect is produced on dogs.

SECTION II.

APPLICATIONS TO THE SKIN.

1. Baths.

During the last five or six years, several most elaborate investigations on the action of baths of various kinds have been undertaken by L. Lehmann, Beneke, and others. The great difficulties and the many sources of error which attend these inquiries have prevented the results from being commensurate with the labour which has been given to the subject; but yet it is evident that the methods employed are correct, and, in the later investigations of Beneke and Lehmann, care has been taken to obviate all possible fallacies. Considering the great use made of baths in medicine, and the beneficial effects which undoubtedly follow their use, there is perhaps no subject in the whole range of therapeutics which is more interesting to the physician than that of their action on the heart, on the nervous and digestive system, and on the eliminating organs.1

Baths may be supposed to act differently, according to the time the bath is used, to the amount of surface covered by the water, to the temperature of the water, and to the substances dissolved in it. Each kind of baths requires a separate investigation.

Baths of Simple Water.

(a) Cold Hip (Sitz) Baths.-L. Lehmann has particularly examined this point. He believed, at one time, that he had succeeded in showing that, from the use of fifteen or thirty minutes' cold sitz bath during fasting hours, there was an increased elimination from the skin, kidneys, and bowels, and necessarily a greater loss of weight of the body than in an equal time without the baths. An examination of his experiments, however, has shown, that as the observations were made at widely separated periods, they are not comparable; and that, in addition, the differences between the bathing and non-bathing days are not beyond the normal limits of variation. To quote, however, his results. As far as the urine was concerned, Lehmann

1 As the limits do not permit more than a summary of the subject, I beg to refer to a review, by the author, in the British and Foreign Medico-Chirurgical Review, Jan., 1859, on the "Influence of Baths on the Excretions," for a fuller criticism of experiments than can be given here.

2 Archiv des Vereins für wissench. Heilk., Band i, p. 521.

3 See the Review above referred to, p. 137.

found the augmented flow to be due partly to water (one half), partly to solids (one half). Of the solids, the increase was owing chiefly to urea (three fourths); the rest, to chloride of sodium. The sulphuric acid was unchanged; the phosphoric, if anything, lessened; the uric acid altered only within the obvious limits of

error.

Böcker1 and Lampe have also examined the effect of the cold sitz bath, and they entirely deny that any effect, beyond the limits of natural variation, is produced on the water, urea, chlorine, sulphuric acid, phosphoric acid, or phosphate of lime. The baths were used for twenty-one minutes.

Dr. L. Lehmann has replied to this paper of Böcker's, and asserts that Böcker's own figures prove that there was in his experiments an increased loss of weight over the non-bath periods. At any rate, it must be said that the influence of cold sitz baths on the urine is not very marked.

(b) Warm Hip Baths.-Dr. L. Lehmann2 has also examined this point, though in a manner somewhat different to that employed in the former series. The urine was determined every hour during fasting, until its composition was stable. A warm sitz bath was then used for fifteen minutes, and the subsequent variations in the urine were put down to this agent, as no other physiological cause of alteration was in action.

When the baths had a temperature of 15° Reau. (65°·75 Fah.) or 25° 31° Reau. (88° to 99°5 Fah.), the water of the urine always augmented, and this to an extent (30 to 150 c.c. per hour) and with a constancy which at first really seems to preclude error. But as the experiments were not very numerous, and as the remarkable fact was noticed, that baths of a temperature of 17° 25° Reau. (70°-88° Fah.) did not have this effect, it is impossible not still to feel a little doubt. Lehmann endeavours to explain the exceptional effect of baths between 70° and 88°, by supposing that decidedly cold or decidedly hot baths irritate the cutaneous nerves, and thus act on the kidneys (relaxation of vessels?); but that baths of medium temperature do not have this effect.

The urea, the uric acid, the chloride of sodium, and the fireproof salts, were also supposed to be augmented by the baths of cold and hot, but not by those of warm water (70° to 88°).

The fasting body lost weight more rapidly with, than without, the baths.

The excretion from the skin and lungs is said by Lehmann to be increased, but it does not appear to be so from the figures he gives. It may be said, finally, that, as in the former series, these ex1 Moleschott's Untersuchungen, Band vi, p. 51 (1859). 2 Archiv des Vereins, Band ii, p. 1.

periments must be considered as merely preparing the ground for more accurate inquiries.

(c) General Warm Baths.-Dr. L. Lehmann has, since his experiments on hip baths, investigated on a larger scale, and with much greater precaution, the subject of the influence of general warm baths. The last and most complete series of experiments comprised the examination of the excreta during ten days without, and ten with, baths; all the ingesta and egesta were measured and weighed, and the external thermometrical and barometrical conditions were noted.

The water of the urine was found to be always and greatly augmented, for the time, by the bath (duration, one hour; temp. 78° Fah.)-nearly fourfold (from 1 to 3.9), but subsequently the amount lessened; so that the urinary water of twenty-four hours was not increased. In other words, the general warm bath is a temporary eliminator of water. Lehmann's experiments seem to me to establish this point, and they are also confirmed by those of Nasse 2 and Poulet. Falck has, however, affirmed the contrary.3

The solids of the urine are also probably augmented; and Lehmann at one time believed he had satisfactorily demonstrated an increase in the amount of urea. But he now doubts whether the experiments were numerous enough to do more than enable him to affirm the probability of this occurrence.* The alteration in the other constituents must be left undecided. The acid reaction of the urine is lessened after all but very hot baths, according to Homolle.5

6

The insensible perspiration (skin and lungs) is often increased; and, apparently, this rather depends on the temperature. Mosler, from the use of very hot baths, has shown that baths of 104-111° Fah. increased the skin and lung excretions enormously; the urine was not augmented; 1 to 1 lbs. of body-weight were lost in an hour. Yet this is afterwards compensated in some cases; for Lehmann found his weight increase under the use of the warm bath, which it could not have done under the same diet if the excretions, on the whole,

1 Die Sooltherme zu Bad Oeynhausen (Rehme) und das gewöhnlich Wasser, Gött., 1856. Archiv des Vereins, 1858, Band iv, p. 18.

2 Einige Beobachtungen über die Wirkung warmer Bäder auf die Harnabsond, Archiv des Vereins, Band ii, p. 265.

3 Archiv für phys. Heilk., 1852, p. 771. The experiments of Falck are very good; the urine was determined every hour. Four series of experiments are recorded; in two there was no increase, but in the other two there certainly was a slight rise, though Falck regards it as immaterial. The temperature of the baths was 88°-95°

Fah.

4 Archiv des Vereins, Band iv, p. 30. 5 L'Union Médicale, 1853.

6 Virchow's Archiv, Band xiv, p. 565.

had not been lessened. The weakness produced in many persons by the warm bath may be due to continued over-excretion; and there may be individual differences, whether the skin or kidneys are most affected.

It is an interesting point to inquire how that which may be termed the one certain fact, viz., the temporary increase of the water by warm baths, is brought about. The most obvious explanation is, that there is absorption of water by the skin. It is impossible here to go into the evidence on this physiological point,' but the latest experiments are, on the whole, opposed to such a solution, and at least show that the absorption is trifling; while the fact that the increase of urine is followed by diminution below the normal amount, does not accord with this explanation.

Another solution is based upon some supposed irritation of, or influence exerted on, the cutaneous nerves, which reacts on the kidneys; producing relaxation of vessels, and lessening the tension with which the vessels act against the lateral pressure of the blood. This hypothesis has no direct proof, but is based simply on the negation of other explanations, and on the well-known fact of the alterations in certain vessels which are produced by hot and cold applications to distant parts.

The other point which seems pretty certain, viz., the lessening of the acidity, is yet unexplained.

(d) General Cold Baths.-The cold bath has very much the same effect as the hot; the urinary water is temporarily increased, and the urea and chloride of sodium are probably also augmented. The "insensible perspiration" is said to be lessened, but on this point more evidence is required.

2

(e) Medicated Water Baths.-The experiments on this point are very incomplete. The curative action of many agents is very striking; the hydrochloric and nitro-hydrochloric baths, for example, are known to have a most useful influence on torpid skin, and Kletzinsky has lately pointed out that no stimulating application to the skin is more powerful than these acids. Chloride of sodium and sulphuret of potassium baths also greatly stimulate the skin, and no doubt act directly or indirectly on the urine, and it is much to be wished that systematic experiments should be made with these substances.

1 For the later writers see especially L. Lehmann, in Archiv des Vereins, Band ii, p. 21, who denies absorption. Poulet, L'Union Méd., 1856, No. 33, who also denies absorption. Vierordt, in the Archiv für phys. Heilk., 1856, p. 575, who admits absorption. Duriau, Archiv Gen. de Med., Fév., 1856, who believes it occurs in some circumstances, but not in others, viz., when the temperature is below the temperature of the body.

2 For additional evidence on this point, see Sir Ranald Martin's late admirable work, on the Influence of Tropical Climates (Appendix).