| Abstrakt: |
As previously described,1embryonic tissue of the salamander, Triturus torosus, when transplanted to Amblystoma embryos, has the peculiar effect of paralyzing the hosts over a prolonged period of time, rendering them entirely insensitive without impeding in any way their normal development, or their growth subsequent to recovery. Aqueous extracts of ground Triturus embryos produce a similar paralysis, of shorter duration, when injected into larvae or adults of Amblystoma. The paralyzing agent was also found present in many cases in adult Triturus female blood, and the suggestion was made that its presence there might be correlated with periods during which it was being deposited in the developing ova. A variety of other experiments performed in the analysis of this phenomenon are summarized in the article cited above. (See also Twitty and Elliott, J. Exp. Zool., Vol. 68.)Until recently there was little information as to the nature of the effect exerted by the substance in question, but the transplantation experiments outlined below offer strong evidence that its action is specific for the nervous system. Briefly, the method of demonstration consisted of bringing nervous and muscular tissue of Triturus torosusand Amblystoma punctatuminto conjunction with one another in crucial combinations designed to reveal which of these 2 major components of the reaction system was affected by the paralyzing agent.Experiment No.1 (control). An inclusive piece from the back of the embryo, consisting of skin and the subjacent neural tube and muscle segments of both sides, was grafted as a unit from the tail-bud stage of Triturus to a position well ventral on the flank of an Amblystoma embryo. The graft developed independently in situ, and upon the subsequent differentiation of its segmental nerves and muscles contracted readily and vigorously when stimulated. |
