The cheek pouch of the hamster as a site for the transplantation of a methyl-cholanthrene-induced sarcoma.

the necessary operative procedures and by the physical confines of the chamber. The advantages realized by using the mem branous cheek pouch of the hamster as a site for transplantation are (a) the tumor grows freely without physical hindrance and in a normal physi ological environment; (b) the same tumor can be observed at successive stages (measured, photo graphed) ; (c) the tumor may be subjected to van ous experimental procedures (chemical and physi cal) with no undesirable disturbance beyond that produced by anesthesia; and (d) transillumination for microscopic study of early stages of growth and vasculanization is practicable. METHOD Hamsters of both sexes, 8-10 weeks old and weighing 90-100 gm., were used throughout this work. The original tumor was induced in hamsters by a series of six weekly subpannicular injections of 0.25 cc. of 0.4 per cent methylcholanthrene in oil of lard. This tumor is tentatively classified as a type of spindle-cell sarcoma, histologically some what different from the benzanthracene-induced sarcoma described by Crabb (4), although no pie tunes of his original tumor were published. The methylcholanthrene-induced tumor was propaga ted by transplantation in the flank of other ham sters and in cheek pouches. This material was the source of the 35 cheek pouch transplants, the growth characteristics of which are reported here. Pieces of hamster tissue such as liver, kidney, adrenal cortex, cheek pouch, epidermis, and skeletal muscle were used to com pare the effect of normal tissue per se with that of the neoplastic tissue. A few minutes before mak ing a cheek pouch transplant, the hamster was anesthetized by an intraperitoneal injection of veterinary nembutal (Abbott) in a dose of 0.1 eel 100 gm body weight. The animal was placed in a spun-steel preparation dish, developed for blood INTRODUCTION