SECRETION PHYSIOLOGY. 355 



double that of seven minutes before, and in experiment 14 was 

 three times as great. In experiment 62, however, there was 

 scarcely any difference. 



The evidence presented in the foregoing pages, if not conclu- 

 sive, certainly indicates that atropine restricts and pilocarpine 

 increases lymph transudation. They may in this manner affect 

 secretions. In any case, if the sympathetic causes its secretion 

 by action on contractile tissue in the gland, there is no longer 

 any reason against assuming that atropin acts directly on the 

 gland cell, in such manner as to check the passage of fluid 

 through it, and thus to prevent secretion. 



d. The Action of Quinine and Nicotine. 



We have considered the three main objections which have 

 been raised against the chorda salivary secretion being an osmosis. 

 There are, also, certain other phenomena which have been 

 thought indicative of the independence of the secretory and di- 

 lator action of this nerve, and, hence, are worthy of a short 

 criticism. 



The first is the action of quinine, which when injected into 

 the gland duct causes a temporary vaso-dilation, but no secre- 

 tion. If, however, the chorda be stimulated, still greater dila- 

 tion ensues and secretion takes place. This secretion is less than 

 normal. Heidenhain^^ interprets this to mean that vaso-dila- 

 tion cannot of itself produce a secretion, but that the secretory 

 fibres must be aroused. (See literature reference No. 21, p. 85. 

 Also reference No. 23, p. 45.) 



The facts may, however, be otherwise understood. Quinine 

 prevents the passage of liquid through the gland cell. This is 

 shown by the fact that ultimately it prevents chorda secretion, 

 even though the gland become oedematous. If the permea- 

 bility of the gland membrane be thus diminished, the slight 

 vaso-dilation caused by the drug may be insufficient to cause a 

 secretion, whereas a larger vaso-dilation on stimulating the 

 chorda might overcome this resistance. Another possibility is 

 that the quinine reaches a portion only of the alveoli, poisons 

 these, and throws their capillaries and arterioles into dilation. 



