HYDROTHEKAPY 867 



pressure is variable and any favoi-able results secured in cardiac cases are 

 independent of the effect on blood pressure. 



Peat and mud baths have a point of thermal indifference considerably 

 above that of water, as high as *5t> C. ; in the absence of convection cur- 

 rents and because* of the non-conducting layer next the skin the effects of 

 heat are equalized and the skin temperature remains more constant. Pos- 

 sibly the chemical action of the acids and salts found in peat and mud 

 and the physical effects of friction and pressure may affect metabolism; 

 but there are no entirely trustworthy data as to the effects of such baths 

 and such as are at hand (Tuszkai; Silber) do not show results that are 

 not attributable to temperature effects on metabolism. Sulphur baths 

 seem to have no specific influence on metabolism (Bain, Edgecombe and 

 Frankling; Winternitz and Popischil). 



Radioactive baths and springs have given the opportunity for the 

 publication of a number of papers dealing with the supposed benefits at- 

 tending their extensive use. Kadium emanation does not enter the body 

 by the skin (Xauelschmidt and Kohlrausch) and when it was added to a 

 fresh water bath no influence on gaseous metabolism was observed (Silber- 

 gleit(a-)). 



Baths and Sweat Secretion 



The influence of baths on the rate of secretion and on the composi- 

 tion of the sweat is of special interest because of a possible vicarious skin 

 excretion under the influence of heat treatment, especially in diseases of 

 the kidney. The data on the composition of human sweat are fragmentary 

 and conflicting- partly because of the wide variety of conditions under 

 which sweat has been collected, because the composition changes with 

 changing rate of secretion (Kittsteiner(a) (&)), varies with the different 

 parts of the body from which it comes, and may vary with the diet (Kitt- 

 steiner(r) ; Berry). It is thus not possible to tabulate the resiilts that 

 have been obtained (Argutinsky; Benedict. (a); Schwenkenbecher and 

 Spitta ; Taylor ' rf). Talbertfw) ). The values for nitrogen elimination 

 under different conditions vary from 0.07 to 0.75 gr. per day (or part 

 of a day), half of which is in the form of urea (Plaggemeyer and Mar- 

 shall). Salt excretion is said to vary from 0.33 gr. to 1 gram in profuse 

 perspiration. Whether nephritics eliminate more solids in the sweat than 

 normal persons seems undecided (Kohler; Tachau; Rigiis; Loofs; Strauss 

 (a)) and figures on the A of the blood in nephritis as influenced by sweat- 

 ing procedure? (Bendix; Grorgopulos) snv not extensive enough to he 

 convincing. Even if perspiration leads to a decrease in the urea of the 

 urine, which it does not, always (Leu be; Dapper (a ); v. Noorden(c)) 

 the amounts of nitrogenous material and salts which can be eliminated 

 by the skin are a very small fraction of those eliminated by the kidney, 



