For the source text click/tap here: Bava Metzia 80
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In selling a cow the seller specified one blemish and said that there were others as well (but he did not mention them by name), the halachah is that (if it emerged that the animal did have the specified blemish) the sale is valid (for the buyer obviously accepted to purchase the animal with that particular blemish).
The Gemara finds a support in a baraita (Tosefta, Bava Batra 4:3): With regard to one who sells a maidservant to another and says to him: This maidservant is an imbecile, she is epileptic, she is crazy [meshuamemet]; but in reality she had only one defect and he inserted it among the other defects, this is a mistaken transaction. But if the seller stated: The maidservant has this defect, i.e., the defect that she in fact has, and other defects, without specifying what they were, this is not a mistaken transaction.
We explore the history of epilepsy or epilambanein in antiquity.