פירוש על תרומות 8:5

שיעור המים – that it would be forbidden because of being uncovered.

Introduction Our mishnah continues to deal with the issue of uncovered water that might have poison in it.

כדי שתאבד בהןמרה – if here was such a great deal that the poison of the snake would deteriorate [its venom] and would be lost in them, there would be nothing of being uncovered, and they would know how much poison a snake it puts in at one time.

The amount of water that is uncovered: enough to negate the poison. There are two explanations to this section. The first explanation is that if there is enough water to negate the effects of the poison, then even uncovered water is permitted. The second explanation is opposite if there is enough water so that one cannot taste the poison, then it is prohibited. If there is not that much water it is assumed that the poison would have taste, and therefore it is permitted.

מרה – the poison that the snake puts in is called מרה/bitterness.

Rabbi Yose says: in vessels [it is forbidden] whatever the quantity, but for water on the ground, it must be forty se'ahs. According to the first interpretation, Rabbi Yose says that if the water is in vessels, even if there is a lot of water, it is prohibited. The vessels concentrate the solution, making the poison more potent. According to the second interpretation, we would have to say that even if there is little water, it is prohibited. Perhaps the vessels would mask the taste. However, if the water is on the ground, the standard measure is forty seahs. According to the first interpretation, more than that is permitted, assuming that the poison is nullified. The second interpretation would seem to have some difficulty in interpreting this line.

בכלים כל שהן – even if they are many, whatever the amount as they are, there is in them on account of be uncovered, when the water is in the utensils.

ובקרקעות עד מ' סאה – there is in them because of being uncovered, more than this, there is none because of uncovering, for the poison is abolished in them. But the Halakha is not according to Rabbi Yosi. But a spring that draws out even a bit, there is nothing in it of uncovering. And uncovered kwaters when they are prohibited to drink them, thusly there are forbidden to give to his cattle to drink and to wash in them his face, hands and feet, and to knead the plaster, and to use them in any manner of usage.