446 



STUDIES IN GENEKAL PHYSIOLOGY 



FIG. 136 



no secretion occurred at the anterior end (in the region 

 $$); a secretion occurred instead close behind S in the 

 region a&, 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 

 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 Amblystomse, 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- 

 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 



FIG. 137 



