TRANSPLANTATION OF LIMBS IN AMBLYSTOMA 2) 
It was suggested by Doctor Harrison that the best way of 
testing the influence of functional activity on the differentiation 
of neuroblasts would consist not solely of removing the end or- 
gan and noting the effects of its absence, but rather of transplant- 
ing the end organ so that it might function in a new environ- 
ment. In this way not only could the effects of removal be noted, 
but still better, the effect of continued function of the trans- 
planted end organ on that part of the central nervous system 
from which its innervation is derived. 
Accordingly, experiments were begun with this problem in 
mind, and while positive evidence has been attained from these 
experiments to show that the functional activity of the trans- 
planted limb will initiate a hyperplasia of the sensory neurones 
contributing innervation to the limb, the results of this phase of 
the experiments are taken up in a separate publication (Detwiler, 
20). The present paper will consider questions mainly con- 
cerned in the formation of nerve plexuses and the function of the 
limbs. 
I wish to express here my thanks to Doctor Harrison for his 
suggestions and criticisms. 
ANATOMICAL 
-Even though a transplanted limb may be well innervated by 
spinal nerves of the host, it is obvious that the degree of function 
of the limb is conditioned by still other factors. Structural de- 
ficiencies of the shoulder-girdle or deficiencies in the shoulder 
musculature would greatly restrict its function, even though 
the limb were copiously supplied with nerves and the structures 
within it were perfectly developed. 
Although the developmental intimacy of the shoulder-girdle 
and limb led Wiedersheim (’92) to conclude that the shoulder- 
girdle can develop only when under the formative influence of 
the free extremity, the lack of interdependence of these two 
systems has been shown experimentally (Braus, ’09, and Det- 
wiler, 718). It has also been shown (Braus, op. cit., Harrison, 
’18, and Detwiler, op. cit.) that in the transplantation of a typical 
