Induction of Sarcoma in the Rat by Cadmium Sulphide Pigment

Abstract

Two injections of 25 mg cadmium sulphide suspended in 0.25 ml. physiological saline were given into the dorsal subcutaneous tissue, one on either side of the midline on a single occasion, in ten 6-month-old female rats of the Chester Beatty strain. A small, hard, mobile nodule developed at each injection site, without evidence of an acute inflammatory reaction of the overlying skin. Six months after injection one of these nodules began to grow rapidly in size, producing a large tumour. During the succeeding four months similar tumours developed at one of the two injection sites in four further rats and at both injection sites in one rat, giving six animals with growing tumours from the group of ten which had been injected. These six animals were killed within one year from the time of injection, when the tumours had grown to 3–6 cm in diameter. The remaining four animals died during this period without producing such tumours, so that there were no survivors after one year. The small nodules in the animals which did not develop tumours consisted of the injected material embedded in dense fibrous tissue.