Among hydrotherapeutic measures sweating, that is, for instance, the Turkish-Irish bath, and steam baths, are most popular as reducing means. Electric sweat baths are also very popular. As a matter of fact very imposing reductions in weight can be attained by these means, but this triumph is very short-lasting. What is actually sacrificed in addition to small quantities of salt and very insignificant quantities of organic products of metabolism, that the kidneys could have gotten rid of much more easily, is water. This water is soon replaced, rapidly if much water is taken, less rapidly if the water intake is at the same time restricted. So much is certain that sweating does not cause a loss of fat. Fat must be starved and worked away. It cannot be sweated away. There is some little justification for sweating procedures in mild degrees of circulatory disturbances, here they aid in removing slight oedemas and in stimulating the peripheral circulation and thereby indirectly also the heart. As soon, however, as one is confronted with circulatory disturbances of a more advanced degree, sweating becomes prohibitive. Arterial disease must also be considered a counterindication.

Carbonated baths are indicated where it appears necessary to exercise a particular influence upon the heart ; but they exercise no effect upon the combustion of body fat.

They should never be employed if there is high arterial tension, a phenomenon frequently witnessed in "plethoric" obese men. In such cases I often have recourse to bleeding in the beginning of the treatment (200 to 250 ccm. of blood) ; this causes a reduction in the blood pressure, and after this preliminary measure carbonated baths are very well borne.

Half baths with a gradual reduction of the temperature of the water, cold rubs, swimming followed by cold douches, are of use not only to stimulate circulatory and respiratory activity, but also to increase the catabolism of fat. These measures withdraw heat that must be replaced by combustion of fat. So far no exact investigations in regard to the degree of caloric output that they produce exist. One can estimate that from 10 to 20 g. of fat must be sacrificed in order to replace the heat lost in a half bath followed by a cold rub. This is a considerable amount of fat. In institutions that treat many cases of obesity cold-water treatments are becoming more and more popular; and this is due to the fact that experience has shown them to be effective not only in reducing fat but in hardening the patients while at the same time counteracting the tendency to dangerous bronchitis and disagreeable hyperhydrosis that such individuals are apt to suffer from.