" It is necessary, especially in hot weather, to wash the feet frequently, as they perspire much, and are more exposed to dust, than any other part of the human frame. The water should be warm, but not too much so, because hot water, thus used, relaxes the fibres, drives the blood upwards, and occasions' head-aches. The proper degree of heat for young persons to wash in, is between 96° and 98° of Fahrenheit; and, for the aged, between 98° and 100°, or somewhat more than milk-warm."
--From The Lady's Book--
Can you imagine people running around with thermometers making sure the temperature of water they are bathing in is within two degrees? Forget that, can you imagine "warm water" being a major health concern?