HYDROTHERAPY 863 



The markedly increased stimulation to heat production (more than 

 double ) from a cold douche as compared with a cold tub bath at the same 

 temperature is evident from the table given above. Winternitz(a) showed 

 that the application of friction in a cold bath caused an earlier fall in 

 temperature and a greater increase in oxygen intake and CO 2 production 

 than a similar bath without friction. He also observed a very marked 

 increase in heat production in a hot sand bath as compared with the re- 

 sults of hot air baths. Two factors, a premature breakdown of physical 

 regulation and a direct stimulation probably come into play. Brush- 

 ing the skin causes rise in temperature in man (Paalzow) ; so also the 

 application of mustard paste. Mustard added to a bath at indifferent tem- 

 perature increased O 2 consumption and CO 2 output by 25 per cent though 

 without affecting the respiratory quotient. By far the greatest interest 

 naturally attaches to sea baths and to the various other natural and artifi- 

 cial baths containing salts. That it is not a question of absorption through 

 the skin is pretty well agreed upon, since the sebaceous secretions forms a 

 barrier to water and all water soluble substances unless they act chemically 

 on the skin. Fats and their solvents on the other hand may be imbibed 

 by the cells or make their way through the capillary spaces and it has been 

 reported l that water soluble substances may be taken up by ether-cleansed 

 skin. Most of the investigations on sea and brine baths seem to show that 

 their effect on energy metabolism is no different from that of baths in ordi- 

 nary water at the same temperature (Jacob(a)(&) ; Leichtenstern) al- 

 though as early as 1871 Rohrig and Zunz showed a greater gaseous exchange 

 in rabbits in a sea salt bath than in a fresh water bath. Winternitz(e) 

 concluded that such baths produce very little change in the metabolism of 

 healthy adults, not more than 15 per cent after baths lasting one hour. The 

 careful work of Loewy and Miiller on sea air and sea baths showed an in- 

 creased metabolism as evidenced by greater oxygen consumption and a 

 decreased respiratory quotient extending beyond the duration of the bath, 

 but there are no comparative data for fresh water bathing with similar 

 climatic influence. The influence of salt water baths on nitrogen and in- 

 organic especially salt metabolism has been the subject of more extended 

 work and discussion. Some early results (l)ommer) tending to show that 

 4 per cent Nad baths caused a marked increase in nitrogen output (in a 

 dog) have generally not been corroborated. The one investigator who does 

 uphold this idea (Robin) probably had too short a preliminary period to 

 observe nitrogen metabolism properly. Koestlin found a decrease in 

 nitrogen excretion after warm sool baths (Stassfurt salt) while fresh water 

 baths had no influence nor did sodium chlorid or magnesium chlorid baths, 

 hut potassium chlorid baths gave the same results as Stassfurt salts from 

 which he concluded that potassium chlorid was the active factor. How- 

 ever, he did not account for fecal nitrogen or for the nitrogen given out in 



'Kahlenberg, private communication to the author. 



