HYDROTHERAPY 267 



temperature to that of the body is indifferent, and the action of 

 tepid water is weak. The colder or the warmer the water in com- 

 parison to the body temperature of the animal, the more pro- 

 nounced is its action upon the skin. In regard to the continuance 

 of action, when cold water is used for the purpose of reducing tem- 

 perature its application must naturally be continued as long as 

 possible. But if the water is employed as a cutaneous irritant, 

 then the therapeutic effect is in direct relation to the shortness and 

 frequency of the individual applications. When a single applica- 

 tion of cold water produces a reaction in the skin in the form of a 

 change in the circulatory relations (hypersemia), the condition dis- 

 appears after a certain interval, and a renewal of the cutaneous 

 irritation is naturally required to again bring about the same 

 reaction with its healing effects upon the organism. One long- 

 contmued application of cold water produces only a single reaction, 

 which occurs in the beginning. For these reasons frequent applica- 

 tions are indicated, and on this accoimt Priessnitz dressings, for 

 example, are changed frequently (on the average every 3 hours). 

 The effects produced under these circumstances are as follows: 

 When the dressing which has been dipped in cold water is first 

 applied, ansemia and cooling of the skin occurs; this is gradually 

 followed by a hyperaemia, which is contmued several hours and 

 which is promoted by the warm overlying dressing. After this 

 period, the circulatory relations are again equalized and in order to 

 produce a new reaction the cold irritant must be renewed; i,e,, a 

 new cold dressing must be applied. 



Failure of a patient to show any reaction in the skin after a 

 proper application of cold water is evidence of great weakness of the 

 nervous system and justifies an unfavorable prognosis. For 

 prophylactic purposes, the frequent use of cold water in healthy 

 animals is recommended to facilitate the occurrence of the reaction 

 and to exercise and strengthen the skin (cold rub-down for horses 

 and cattle, washing). 



2. The circulatory apparatus is influenced in very different 

 directions by hydrotherapy. As already observed, cold water 



