The medical Head of any hospital may donate the body of any deceased individual dying of known causes to the Head of any medical school or institution for carrying out by him or any other licensee in relation to that body any matter referred to in subsection (2) of section 1, if the Head of the hospital is satisfied that that body has not been claimed by the surviving wife or husband, or in the absence of such wife or husband, by any known relative of that individual falling within such class of relatives of that individual as may be prescribed, for a period which in his opinion has been unreasonably long.