Vol. 6. 1920 
ZOOLOGY: S. R. DETWILER 
695 
to X-rays at temperatures up to a dull red heat. There is usually color 
change as mentioned under (6) and a distinct maximum of brightness 
at some intermediate temperature. 
^ In this statement reference is to established cases of luminescence. Exception 
is made of the rather numerous instances in which radiation of an unusual character 
is ascribed to luminescence without actual demonstration of the fact. The present 
author more than once has made such assumptions and believes them likely to be 
verified. 
2 Lenard and Klatt, Ann. Physik, Leipzig, 15, 1904 (425). 
3 Wiedemann and Schmidt, Ibid., 56,' 1895 (218). 
FUNCTIONAL REGULATIONS IN ANIMALS WITH COMPOSITE 
SPINAL CORDS 
By S. R. Detwmr 
Peking Union Medical College;, Peking, China 
Communicated by R. G. Harrison, October 7, 1920 
In several recent series of experiments,^ involving the transplantation 
of the forelimb in Amblystoma embryos, a number of points were brought 
out by the author bearing upon the question of the functional readjust- 
ment of the peripheral nervous system in response to the altered condi- 
tions. The cardinal points may be summarized as follows: 
(1) When the limb is transplanted to an abnormal (heterotopic) position, 
there is a striking tendency for its innervation to be derived from the orig- 
inal limb level of the cord, and only when this is totally or in part accom- 
plished, is the limb capable of movements which are well coordinated with 
those of the opposite intact appendage. 
(2) Transplanted limbs which are not supplied by the normal limb 
nerves exhibit a degree of function which is directly correlated with the 
region of the spinal cord from which the nerves are derived. The motility 
of the appendage is more perfect when its nerves come from segments of 
the cord adjoining those which contribute the normal limb nerves. 
(3) The gradual loss of function as limbs are transplanted further and 
further away from the normal situation is attributed to increased defective 
connections within the central nervous system and not to a corresponding 
decrease in effective peripheral efferent innervation nor to deficiencies in 
in the skeleto-muscular mechanism of the limb and the shoulder girdle. 
(4) Peripheral nerves supplying a transplanted limb are larger than 
their counterparts which have no connection with a limb. Critical ex- 
amination has shown this enlargement to be due to a hyperplasia of the 
afferent neurones with no evident over-production of cells on the motor 
side. 
The fact that structurally complete transplanted limbs with an ade- 
quate peripheral nervous mechanism, derived from the extra-limb level 
