Ruling 203. If the blood of a human being, or of an animal whose blood gushes out [when its vein is cut], is sucked by an animal that is commonly known to have no blood, such that it may be absorbed in that animal’s body – like when a mosquito sucks blood from a human being or an animal – then that blood is pure. This is called ‘transfer’. As for the blood that a leech sucks from a human being for treatment, as it is not known whether or not that blood becomes part of its body, it is impure.

Ruling 204. If a person kills a mosquito that had sat on his body and the blood sucked by the mosquito comes out of it, that blood is pure – even if the time that elapsed between the sucking of the blood and killing the mosquito was very little – because the blood was in the process of becoming food for the mosquito. However, the recommended precaution is that in this situation, one should avoid the blood [i.e. it is better not to treat it as being pure].