The use of water as a healing agent dates from the remotest antiquity and is, today, practised by nearly every physician. The school of medicine which depends upon water as the healing agent is called "Hydropathic" and the use of water as a remedy, hydrotherapy. The early records of Asyria, Egypt and China, show that water was a very common healing agent. Among the Greeks and Romans the bath was a public institution, and some of the most remarkable buildings, especially in Rome during the days of its greatest prosperity, were those devoted to the bath. The temperature of the water has a great deal to do with its curative power, and hence cold, warm and hot water and even steam are constantly employed. The so-called Turkish bath depends largely upon the vapor of water at a high temperature for its therapeutic effects. In the writings of Hippocrates a very detailed description of the use of water as a remedial agent is found. In the warfare against the infectious organisms of the body the remedial agent is necessarily carried in solution. Hence water becomes not only the carrier of foods, but also the carrier of remedial agents. The percentage of water in the blood is a dominant factor in the normal activity of that liquid tissue. In certain diseases, such as cholera, the water content of the blood is greatly diminished, and speedy fatality attends the depletion of the water supply.