SECRETION PHYSIOLOGY. 357 



brane. Plainly here are all the requisites of a delicate osmotic 

 mechanism adapted to the most rapid osmosis. 



(2) Chorda secretion is closely dependent on blood supply. 

 (Compare p. 342.) Heidenhain has shown that partial occlusion 

 of the artery diminishes the rate of secretion (p. 88, Breslau 

 Studien IV.) 



(3) If the osmotic equivalent of the blood be increased by the 

 injection of strong salt solutions the secretion is diminished or 

 altogether inhibited. ^^ ^^ 



(4) If the osmotic equivalent of the blood be decreased by the 

 injection of water the rate of secretion is in creased. "^'^ 



(5) The rate of secretion is increased, other things equal, by 

 an increase in the rate of blood flow through the gland. '^^ '^^ 



(6) The rate of secretion diminishes when the hylogens are 

 washed out of the gland. (Paralytic secretions, secretion after 

 long stimulation.)^'^ 



(7) Substances may be absorbed with extraordinary rapidity 

 when injected into the duct (nicotine, atropine). 



(8) If the percentage of salts in the blood be increased the per- 

 centage of salts in the saliva increases also. If the percentage of 

 salts in the blood be decreased, the percentage of salts in the 

 saliva decreases also."^^ ^^ ^^ 



(9) If the artery of the gland be clamped for 20—30 minutes, 

 and the blood thus completely cut off from the gland, on read- 

 mitting the blood a vaso-dilation ensues, so that the blood rushes 

 red from the gland veins, and this vaso-dilation is accompanied 

 by a spontaneous secretion. Stimulation of the chorda in no 

 way alters this secretion during the first minute, nor until the 

 dilation has somewhat diminished. This spontaneous secretion 

 is a close duplicate of that observed by Levy in the secretion of 

 sweat. [Experiment V (a).] 



Although this spontaneous secretion might, perhaps, be ex- 

 plained by supposing that a direct stimulation of nerve-end or, 

 cell by the oxygen has taken place, it seems more probable to 

 me to class it with the spontaneous secretion of sweat in the 

 horse, following section of the cervical sympathetic, and to refer 

 it to the direct effect of vaso-dilation. 



Annals N. Y. Acad. Sci., XI, October 13, 1898 — 24. 



