Hydrotherapeutic procedures and baths are of great hygienic and therapeutic importance for girls at the menarche. In healthy girls at this period of life, a cold sponge-bath lasting one or two minutes, the temperature of the water ranging from 10° to 20° C. (50° to 63° F.), taken either on rising in the morning or immediately before going to bed, is a valuable means for hardening the whole body; equally useful are cold shower-baths, lasting from a few seconds up to half a minute. If the girl is somewhat anæmic, it will be well for her to take a glass of warm milk or a cup of tea half an hour before the bath, in order to guard against too great an abstraction of heat. Cold bathing in rivers, when available, may also be recommended. In cases in which a considerable degree of anæmia or chlorosis is present, cold baths and every form of strong mechanical stimulation by the use of water, douches and the like, are to be avoided, since we have to fear both excessive abstraction of heat and overstimulation of the nerves. In such anæmic and chlorotic patients, either partial washing with lukewarm water or general lukewarm baths, the temperature of which may be gradually and cautiously lowered, either on rising or at bedtime, have a refreshing and stimulating effect. In girls who are in other respects healthy, but in whom the menarche is delayed, and in whom menstruation, when begun, has been scanty and irregular, cold sitz-baths of short duration, the abdomen being simultaneously douched from a considerable height, or cold shower-baths in combination with powerful abdominal douches, are often of value. Recently, hot air and vapor baths have been especially recommended for girls suffering from chlorosis, at first, by _Scholz_ and _Schubert_, in association with phlebotomy, but also without this. _Kühne_, for example, has seen the most satisfactory results follow the simple use of sudatory baths in cases of chlorosis; improvement was manifested by an increase in the corpuscular richness of the blood, an increase in the hæmoglobin-richness, and an increase in the body-weight. In cases of chlorosis, _Traugott_ also has seen favorable results follow the use of hot air baths and the consequent diaphoresis.