This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
(1) Stimulation of the Circulation. As before stated, cold water applied to the surface of the body arouses and stimulates the circulation all over the system. Blood counts before and after a cold-water application show a very marked increase in the number of red and white blood corpuscles. This does not mean that the cold water has in a moment created new blood cells, but it means that the blood has been stirred up and sent hurrying through the system, that the lazy blood cells which were lying inactively in the sluggish and stagnant blood stream and in the clogged and obstructed tissues are aroused to increased activity.
Undoubtedly, the invigorating and stimulating influence of cold sprays, ablutions, sitz baths, barefoot walking in the dewy grass or on wet stones and all other cold-water applications depends largely upon their electromagnetic effects upon the system. This has been explained in Chapter Ten, "Natural Treatment of Acute Diseases."
(2) Elimination of Impurities. As the cold water drives the blood with increased force through the system, it flushes the capillaries in the tissues and cleanses them from the accumulations of morbid matter and poisons which are one of the primary causes of acute and chronic diseases.
As the blood rushes back to the surface it suffuses the skin, opens and relaxes the pores and the minute blood vessels or capillaries and thus unloads its impurities through the skin.