A new hanging-drop method which avoids fogging the coverslip or depression chamber is descr. A depression slide is filled with liquid petrolatum, a coverslip bearing a small amt. of peritoneal fluid containing tumor cells is then inverted over the paraffin well. Slight pressure is applied to the cover-slip and the excess oil is removed. Remarkable phase contrast photographs of these preparations depict stages in bipolar, tripolar, and quadripolar divisions of tumor cells. Evidence for correlating rise in temp. with a decrease in the duration of each mitotic phase is presented.