Distribution of Metastases in the Brown-Pearce Tumor. IV. Effects of Site of Inoculation. ∗

Abstract

It has been shown that the distribution of metastatic foci in the Brown-Pearce tumor of the rabbit (a) is not disturbed by the breed of animal used for transplantation, 1 (b) has remained constant over a period of 15 years of transplantation, 2 and (c) is not affected by treating the animal with an homologous material. 3 All the inoculations in the 3 series were intratesticular and unilateral.

The present paper concerns the possible effect of intracutaneous inoculation upon this constant and characteristic distribution of metastases. To determine this effect a comparison was made of the distribution of metastatic foci in rabbits injected intracutaneously with the same distribution in rabbits injected intratesticularly. 3

Observations were made upon 469 rabbits. Thirty-two rabbits 8 to 18 weeks old were injected intracutaneously over the right scapula, first with 0.3 cc of an homologous material, and 2 weeks later with 0.3 cc of a saline emulsion of Brown-Pearce tumor (Table I). Four hundred thirty-seven young adult rabbits were injected intratesticularly with 0.3 cc of a saline emulsion of Brown-Pearce tumor; 44 of this group also received homologous material. 3 An additional number of rabbits injected intracutaneously with the tumor alone are not included in this analysis because no visceral metastases were observed. (Table I.)

Many sites had too few metastatic foci for adequate statistical analysis and are therefore excluded from this comparison. The sites affected were arranged in 2 groups (Table II), according to whether spread seemed to have occurred by tissue spaces and lymphatic channels or was hematogenous. There were 7 sites in the former and 13 in the latter group. Both the actual and the expected values are presented, with their totals. To test the significance of the differences between actual and expected values, the figures x²/m were calculated. 4