As we learned on yesterday’s daf, there are a number of cases where internal organs may be entirely removed from an animal, yet it is not rendered a tereifa, i.e. it is not a terminal condition that will lead to the animal’s imminent death.
The kidneys are essential organs that serve the body as a natural filter of the blood, and remove wastes which are diverted to the bladder. Furthermore, they function as a regulator, maintaining the acid-base balance and regulating blood pressure by maintaining the salt and water balance. The kidneys also are responsible for the reabsorption of water, glucose and amino acids; they also produce hormones and enzymes. A human being whose kidneys are removed would face certain death, yet the stomachs of ruminant animals contain a mechanism that removes wastes to the stomach so that such an animal could survive even if its kidneys were removed.
On today’s daf, Rakhish bar Pappa teaches that although missing kidneys would not render the animal a tereifa, if one of the kidneys is diseased, then the animal would be rendered a tereifa. The Gemara continues by teaching that in Israel they limited this ruling to a case where the disease reached until the white area beneath the animal’s loins.
Rashi explains that the case is when one of the kidneys becomes infected and is full of pus. Others offer different explanations for the disease that is discussed here. According to the Rashba and the Tosefot HaRosh, the kidney is considered diseased if the tissue of the kidney weakens and begins to dissolve; the Rambam rules that it is diseased if the kidney falls apart when held up. According to the Ba’al HaIttur the case is when the color of the kidney changes to white, indicating a serious condition.