“…Several studies indicate that the pineal gland may have an in fluence on tumor growth: Engel [1,2,3,4,5], Bergmann and Engel [6], Hofstatter [7], Sander and Schmid [8], Rodin [9], Barone and Das Gupta [11] postulated that pinealectomy affects both pigmented and non-pigmented tu mors in rats. Lapin [12] studied the influence of pinealectomy and thymectomy on the growth and formation of metastases of the Yoshida sarcoma in rats.…”