Movements in Transplanted Limbs.

Abstract

In the course of the experimental work involving the use of the amphibian limb disc, many of the effects of this developing structure upon the nervous system have been discovered. Most of the transplantations have involved placing the limb disc posterior to its normal location. Such transplants show very weak function unless they are innervated by at least one of the nerves which under ordinary conditions would go into the normal limb. Detwiler and Carpenter 1 have studied coordinate movements in both the transplanted and normal limbs and have found that coordination is an expression of an innervation common to both the normal and the transplanted limb through some one of the bronchial plexus nerves. Such coordination is lost as soon as the communicating branches of such nerves are cut.

The work here reported deals with transplantations made in testing the growth of various isolated parts of the amphibian nervous system. The operation, in which the limb and associated tissues were used in order to block the growth of the nervous system, involves the removal of a part of the nervous system and the transplantation into the wound of a rectangular transplant of embryonic tissue which includes the rudiment of the limb and also of the pronephros. The establishment of a block within the nervous system has been reported previously. 2

The transplants have been located either anterior or posterior to the normal limb level and their reactions noted. Their regional locations are (1) above the notocord in the region formerly occupied by the ninth, tenth and eleventh spinal cord segments; (2) in the region formerly occupied by the tenth cranial, the first and second spinal segments; (3) in the region of the mesencephalon and (4) in the orbit.