While the Gemara on yesterday’s daf (=page) discusses ritual hand washing during and after the meal, on today’s daf the Gemara turns to the question of ritual hand washing that must be done before the meal begins.
In the Gemara, Hizkiyah is quoted as prohibiting the use of hot water for ritual hand washing before meals, as well as the use of water from the hot-springs in Tiberias – although he can dip them in the water as in a mikveh.
Regarding the hot-springs of Tiberias, Rabbi Yohanan rules that it can be used as a mikveh for the entire body, but not to wash one’s face, hands and feet.
Ultimately Rav Papa explains that all agree that the hot-springs of Tiberias can be used as a mikveh in their place. Additionally, all agree that water from those springs cannot be used for hand washing if they are removed in a bucket or some other vessel. The difference of opinion is limited to a situation where pipes are laid through the hot-springs so that the water that runs through the pipes would be heated up. Hizkiyah prohibits the use of those waters, lest they be confused with the actual water from the hot-springs; Rabbi Yohanan is not concerned with that possibility.
The Tiberias hot-springs, near the Sea of the Galilee, contain geothermally heated groundwater that is at a constant temperature of 60 degrees Celsius (140 degrees Fahrenheit). The waters are high in mineral and salt content and have been recognized for centuries as having medicinal value. Even though these waters were not used for drinking because of their bitterness, nevertheless they were used by the local people to heat fresh drinking water by means of pipes that were inserted in the hot springs.
In explanation for why the waters of the Tiberias hot-springs cannot be drawn for hand washing, the commentaries note that they are bitter to the extent that they are not even drunk by dogs.