446 STUDIES IN GENERAL PHYSIOLOGY 
no secretion occurred at the anterior end (in the region 
SS); a secretion occurred instead close behind S in the 
region ab, that is to say, in the regions directed toward the 
anode of the animal, which still possessed a spinal cord. 
The destruction of the anterior portion of the spinal cord 
SS had no effect upon the secre- 
tion when the current was sent in a 
homodromic direction. In both cases 
secretion occurred in the region cd 
(Fig. 137). I have often repeated 
this remarkable experiment, always 
with the same result. It might be 
FIG. 136 thought that the destruction of the 
spinal cord had an inhibiting effect upon the secretion of 
those glands of the skin which are connected with the de- 
stroyed portion of the spinal cord, and I was myself inclined 
to believe this. When I subjected pieces of Amblystome, in 
which the spinal cord had been destroyed either entirely or 
in part, to a transverse current, I found to my surprise that 
secretion still occurred at the anode, it mattered not whether 
the spinal cord was destroyed or not. In view of this fact 
only one other assumption remains, namely, 
that two sources exist for the stimulation 
of the glands of the skin through the gal- 
vanic current. One of these is stimulation 
of the central nervous system; the second, 
the direct stimulation of peripheral organs, 
either the peripheral nerve fibers which go 
to the glands of the skin, or the nerve end- FIG. 137 
ings in the skin, or perhaps the glands themselves. In 
dealing with a current running longitudinally we have to do 
with only the first source, and polar stimulation of the 
central nervous system occurs at the anode. In the case of 
a transverse current we have to deal, in addition to this, or 
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