Observations on Gye's work with the Rous sarcoma.

Abstract

The writer wishes to report briefly the results of experiments carried out during the last seven months in attempting to repeat and amplify the experiments of Gye 1 on the Rous chicken sarcoma. The latter interpreted his results as meaning that two factors were involved in the production of this tumor; first a specific, non-living, chemical factor found only in extracts of the neoplasm; and second, a filtering virus, capable of being cultivated in vitro under certain conditions. The latter was also obtainable from cultures of mammalian tumors. Neither substance alone was capable of producing a tumor, together they were active. The media used in cultivation of the virus contained broth, rabbit serum and chick embryonic tissue. No controls using un-inoculated, but incubated media of this type to replace virus were quoted in the original paper. In personal communications, Gye lias reported to the writer that such controls have been carried out and in his hands have proved negative. Murphy, 2 on the contrary, has recently presented evidence that media uninocu-lated with tumor, but containing either chick embryonic tissue or mouse placenta, i. e., rapidly growing tissues, and incubated anaerobically, could be substituted successfully for virus cultures. Until agreement can be reached on this and other points, judgment of the interpretations to be placed on the phenomenon may well be reserved.

In this laboratory the repetition of the type experiments of Gye have proved to be far from easy. The experiments thus far have used something over two hundred chickens and have served to point out the difficulties to be expected, and perhaps to suggest means of overcoming them.

There are marked individual variations in susceptibility to small doses of tumor extract manifested even by pure Barred Rock chickens, which we have used exclusively.