The fate of embryonic tissue implanted in the mother

Abstract

The following experiments were done primarily to ascertain whether there exists, specific to the pregnant animal, a substance favoring the growth of embryonic tissue.Many pregnant white mice were hysterectomized (leaving the ovaries in situ), and a measured portion of the hashed embryo implanted through a needle subcutaneously. The animals showed themselves only slightly susceptible to infection at operation, and in the great majority the laparotomy wound healed promptly and the general health remained good. It was found that the embryonic tissue grows profusely when implanted in the mother, yet not better than in certain unoperated, alien hosts. No evidence of a favoring substance specific to the pregnant animal was obtained.In a number of experiments two mice were hysterectomized, and separate grafts of the hashed embryo from each were made in both, using the subcutaneous tissue of the flanks as the site of implantation. In general the embryonic material grew better in the animal that had furnished it,—...