This paper presents clinical, pathologic and biologic evidence that "temperature" plays one of the most important parts in the activation of embryonic cell growth. Preliminary laboratory and clinical experiments continue to emphasize the importance of certain critical temperature levels in such embryonic cell activation. These studies have been submitted to careful analysis in certain directions. As far as we can determine, while the hyperpyretic state has been explored rather widely clinically, reports of little or no work have been published on the effect of reduced temperatures in disease, particularly in its application to the cancer problem. Our observations have opened up an entirely new vista and approach. We submit this material as factual data, in the hope of stimulating interest and provoking further investigation in a field as yet practically untouched. After a study by one of us (Fay) of body surface temperatures, based on a neurologic dermatomere plan, it