338 MATHEWS. 



tion may cause the secretion. It is conceivable that this post- 

 mortem secretion might be due to the flow of blood from the 

 veins and arterioles into the capillaries, owing to the active dila- 

 tion of the latter during chorda stimulation. This explanation, 

 it is true, necessitates the assumptions that the chorda tympani 

 causes, on stimulation, an active dilation of the capillaries, or 

 veins, as well as of the arterioles, and that that dilation in some 

 manner makes it easier for the liquid to pass out into the secre- 

 tion. Both of these assumptions are difficult of proof, and in 

 the limited time at my disposal I have not been able to get 

 demonstrative evidence, either of their truth or error. There is 

 some reason to believe, however, that they may possibly be true. 

 That liquid passes out of the capillaries into the secretion of 

 the submaxillary gland because of an attractive pull exerted 

 upon it by some constituents of the gland cells, has been sug- 

 gested both by Ludwig and Heidenhain. To the evidence pre- 

 sented in favor of such a view by Heidenhain, I have nothing to 

 add, and in the normal condition of the capillary and gland 

 wall, I presume that the hypothesis is true. Ludwig supposed 

 that during chorda stimulation the attractive pull of the cell was 

 increased, owing to the formation of substances in the cell pos- 

 sessed of a higher endosmotic equivalent. Heidenhain believed 

 that the attraction of the cell for the liquid in the blood was 

 constant, but that on stimulating the chorda, the turgor of the 

 cell diminished owing to the passage of liquid into the gland 

 lumen, and water was thus enabled to enter the cell from the 

 blood. Both of these explanations, as will be noticed, assume 

 that in some manner the effectiveness of the attractive pull of 

 the cell is increased during nerve stimulation and water enters 

 the cells independent of the state of the vascular system. The 

 question which confronts us and which it was supposed this 

 post-mortem secretion settled is this : Does stimulation of the 

 nerve cause secretion by increasing in some manner the attrac- 

 tive pull exerted by the gland cells on the hquid of the blood, 

 or does it indirectly render effective by vaso-dilation an attrac- 

 tion which is constantly exerted by the cell on this liquid ? 

 This is a very difficult point to determine. The endeavor 



