Handling Human Chromosomes by A Coumarin Technic

Small pieces of nonneoplastic and neoplastic human tissues, mainly from cervix uteri and soon after removal by biopsy, are transferred to a saturated aqueous solution of coumarin for 5-10 min, after which they are put into the regular aceto-carmine mixture for about 1 hr. A squash preparation is made with moderate pressure and the cover glass is sealed by a mixture made of equal volumes of Canada balsam and hard paraffin. These temporary preparations are suitable for the study of chromosomes for about 15 days, after which they can be made permanent by following one of the usual procedures that employ dehydration and clearing.