Experiments in Transplanting Limbs 267 



small branches are given off to supply the primary limb. One fol- 

 lows the sciatic artery a short distance down the thigh, and is to be 

 regarded as a rudimentary n. ischiadicus. The other runs to the 

 skin of the thigh and corresponds in position to the r. cutaneus 

 femoris lateralis. The secondary limb receives a much larger 

 bundle of fibers. These run into a large n. ischiadicus, which 

 however ends before it reaches the knee. It gives off in the upper 

 part of the thigh a distinct r. profundus posterior. 



The limbs derived from the nerveless bud also contain nerves. 

 A branch from the seventh spinal nerve supplies them. This 

 nerve runs first as a compact bundle. Just before passing the 

 pelvic cartilage it becomes frayed out to some extent, but may 

 nevertheless be followed nearlv to the knee, giving off a r. pro- 

 fundus posterior. 



The secondary limb is much less advanced in development than 

 the primary but it receives a large branch of the above mentioned 

 nerve, which runs into the thigh for a short distance in the position 

 of the n. ischiadicus. 



In this case, as is readily seen from the figure, all four of the 

 transplanted limbs are considerably less advanced in develop- 

 ment than in the first case described. It is possible that had the 

 larva been kept alive for a longer time, the nervous system, of the 

 limbs would have become more complete. It is worthy of note 

 that in this case the primary normal leg has the least complete 

 innervation of all the four transplanted appendages. 



Experiment IV."^"^ This experiment, made upon Rana larvae, 

 differed from the others in that the limbs were transplanted to the 

 back immediately behind the anterior lymph hearts. As before, a 

 normal left bud was placed on the left side and a nerveless right on 

 the right. The larva from which the latter was taken had lived 

 nine days after extirpation of its spinal cord. Sections of this > 

 larva show that there are no nerves posterior to the vagus, the 

 funicular fibers not even having grown out from the brain. The 

 yolk is entirely absorbed except for a few granules in the intestinal 

 epithelium. 



^'Record number, Tr. Eit. ii. 



