Donating blood

Mrs. Carl and I spent this morning at Hadassah Hospital in Ein Kerem donating blood for the son of friends (and the son-in-law of other friends - same person) who is undergoing a bone marrow transplant. An hour to get there, an hour to be there, and an hour to get back (traveling by bus - our car has departed this world and we have not yet bought another one).In Israel, the hospitals expect that