the result of the removal for a certain time of external stimuli from the sensory nerves.

When sufficient heat is applied to induce an elevation of the temperature of the blood, the nervous system suffers a sort of shock, which is followed by a distinct sense of fatigue. The moderately hot douche, with water from 100° to 110°, although producing a slight elevation of the central temperature, constitutes a powerful means of depression. The tepid bath has the same influence. Fatigue and exhaustion are effects of more energetic procedures, such as the hot bath and the vapor-bath, which produce a more marked elevation of temperature, and at the same time a profuse diaphoresis. A tendency to sleep may also follow.

Hot applications act more energetically than cold upon the processes of nutrition. Bartels, in 1864, noted in man an increase in the excretion of urea after vapor-baths; Naunyn has observed the same fact in dogs. G. Schleich found an increase of 29 per cent. in the excretion of urea in persons living under a uniform regimen and taking baths lasting an hour at a temperature of 104° to 108°. This azoturia persisted for several days after the cessation of the use of baths. A. Frey and Heiligenthal have obtained different results. They found a diminution in urea-excretion under the use both of the hot-air and the vapor-bath, but a great increase in the elimination of uric acid. The question, therefore, cannot be considered as definitely settled, and further study is necessary.

PART IV.

HYDROTHERAPEUTIC MEASURES.

HYDROTHERAPEUTIC procedures are divided into the simple, in which only one hot or cold application is made, and the compound or mixed.

In beginning the study of the procedures in which cold is employed, it is well to discuss briefly certain general precautions which the use of these means imposes upon us.

Care should be taken to prevent chilling and to secure the proper development of the secondary or post-operative effects which constitute the reaction.

It is necessary before applying cold to the surface of the body that the patient be under normal conditions as regards the distribution of temperature. Sometimes he is prepared for the procedure by mild friction, or by making him take a moderate amount of exercise.

The room should have a suitable temperature, from 70° to 74°. As regards the preferable time, it is best to make the application at the moment of rising, or at least in the morning, in order to secure a speedy and vigorous reaction. The application should not be made immediately after a repast nor just before retiring at night.

The douche and the full bath, being employed to produce an intense cooling, should be of short duration and should be interrupted at the appearance of the second or great chill. When it is necessary to produce a powerful cooling effect, the development of the chill is delayed by means of movements or by practising friction. It is the rule to permit an interval of several hours to elapse between two applications in order that the organism may remain in a normal equilibrium for a sufficient length of time. At most two applications, separated by a space of from six to eight hours, are made in a day, save when it is necessary to combat fever. In every case the return of the peripheral warmth should be secured after each appli

cation. It may be incited by exercise, by friction, by warm clothing, etc.

Whenever, during the employment of cold, a tendency to collapse develops in spite of the observance of the precautions just given, resort should at once be had to spirituous drinks, or even to the immersion in a hot bath.

It is a useful provision to take note at the commencement of the treatment of the impressionability of the individual and his power of reacting from cold applications.

Whether we use cold or heat in hydrotherapeutics, however, we distinguish procedures with percussion from those without percussion. The type of cold applications combined with percussion is the douche, the hydrotherapeutic agent which, beyond doubt, occupies the first place.

Douches. In the case of the general douche, it should be administered with water, the temperature and the force of projection of which can be varied at will. The principal varieties of douches are: the shower-douche, the column-douche, the douche of concentric layers, the sheet-douche, the circle-douche, and the movable-jet douche.

The management of the douche-chamber and its appurtenances should leave nothing to be desired. Under the douche, within reach of the patient, supports should be arranged for the arms, which will be useful in case of respiratory embarrassment; means should also be provided for a foot-bath before the douche, if the procedure is deemed necessary.

In the beginning of the treatment, cool water, at a temperature of from 66° to 74° F., is employed, and a low pressure equal to about seven pounds. Later the temperature of the water may be at 60°, then 55°, and rarely even as low as 50°.

At the commencement the duration of the douche is only twelve to fifteen seconds; later from thirty to sixty seconds, rarely longer. The longest douches occupy two minutes. The pressure of the water is ten to fifteen pounds, or at most twenty to twenty-five.

For the administration of the shower-douche the water is conducted to a disk about eight feet above the floor, having numerous perforations, each one-eighteenth to one-eighth inch in diameter. When the holes are one-sixteenth inch in size the water falls as spray; when one-eighth inch, in the form of heavy rain.

The column-douche is a large jet of water issuing at a certain angle from a large brass tube, having a diameter of one-fourth to three

fourths of an inch. The douche thus produced constitutes the most energetic mode of percussion. It is applicable only to parts not very sensitive, as the large muscular masses of the limbs, and is, in the beginning, continued for not more than four or five seconds. Formerly this douche was much employed, but at the present day it has been almost completely abandoned.

The dauphin is a diminutive column-douche.

The douche of concentric layers is also but rarely employed. It consists of an end-piece having two concentric slits (Fig. 10) one