ABSTRACT
The subject may be approached by considering first the possible influences of an organic connection between two entire developing individuals, and next the transplantation of organs and smaller parts from one embryo or young individual into another. Nature has arranged for us a most illuminating demonstration of the effects of fluids produced in the body of one developing embryo on the character of development in its sister twin. Combinations of different embryonic persons or parts of embryos may completely modify the developing personality and actually change future eyes into skin, but such combinations are entirely without influence upon the species characteristics of the cells involved. In uniting random pairs of salamander embryos before sex differentiation has occurred, the chance expectation of sex combinations will be one pair of potential males, to two pairs of male with female, to one pair of females, a 1:2: 1 ratio.
