SECRETION PHYSIOLOGY. 341 



tive dilation of the capillaries, as well as a dilation of the arte- 

 rioles. (2) That the sympathetic is able to overcome the 

 chorda*s action on the arterioles, but not its action on the capil- 

 laries. This is shown by the following fact : If, during strong 

 stimulation of the sympathetic, the chorda be irritated by a cur- 

 rent which by itself is barely able to arouse a secretion, a secre- 

 tion ensues which is certainly as large, if not somewhat larger, 

 than the chorda alone would cause. Such a weak stimulus of 

 the chorda is, however, unable to neutralize the sympathetic's 

 constrictor action on the arterioles, as shown by the observa- 

 tions of V. Frey. It will be necessary to assume, hence, that 

 the arterioles have remained contracted, while the capillaries 

 have dilated and blood has entered them from the veins produc- 

 ing a secretion analogous to the post-mortem chorda secretion. 



I endeavored, in a variety of ways, to obviate with certainty 

 all possibility of the chorda's dilator action. By the injection 

 of supra-renal extract into the circulation I hoped to cause 

 such an intense peripheral constriction as to neutralize the di- 

 lator action of the nerve. I am indebted to Dr. R. H. Cunning- 

 ham for this suggestion. After division of the chorda I injected 

 into the jugular vein the whole of a normal salt extract of two 

 powdered supra-renal capsules of another dog. I found, how- 

 ever, that the injection was followed by a slow constant secre- 

 tion of what appeared to be sympathetic saliva, and that this 

 secretion was increased at all times by a very weak stimulation 

 of the chorda. Indeed, the chorda caused a larger secretion 

 after the injection than before, probably due to the v^aso- con- 

 striction in other areas of the vascular system. This result was 

 so discouraging that I did not attempt to repeat it. 



Heidenhain remarks that large doses of physostigmin cause 

 such an intense constriction of the arterioles of the gland after 

 division of the chorda that stimulation of the latter nerve is un- 

 able to cause either a vaso-dilation, or secretion. Unfortunately, 

 Heidenhain does not ^w^ a full account of the experiment. 

 Were it true that the drug produces this effect within three or 

 four minutes of its injection, it would be, I believe, conclusive 

 evidence that secretion can not ensue in the absence of vaso- 



Annals X. Y. Acad. Sci., XI, September 13, 1898 — 23. 



