Wilhelm Winternitz (1834 - 1917) was an Austrian balneologist, scientist and doctor. He built on Vincent Prießnitz, expanded hydrotherapy and founded a spa in Kaltenleutgeben in 1865. In 1899 Wilhelm Winternitz was appointed the first director of the hydrotherapeutic clinic at the General Polyclinic in Vienna.
Effects of the water depending on its temperature:
If cold water has a short duration or moderately cold water has a long duration effect on contractile tissues, such as vessels, muscles, etc., it stimulates them and forces them to contract.
If, on the other hand, very cold water is applied over a longer period of time, the stimulus is replaced by overstimulation, a slackening. This is why a cold air stream can only contract the vessels for a short time and make the affected parts paler, whereas the same air stream can cause over-stimulation if it is applied for a longer period of time, i.e. the slackening causes the parts to become redder.
From: Text on the basic principles of hydrotherapy after Dr. Winternitz 1871, Medical University of Vienna, collections and history of medicine.