314 MATHEWS. 



The results of these experiments, in conjunction with those 

 following, are most readily explicable, I believe, on the muscu- 

 lar theory. The augmented saliva, in whatever manner pro- 

 duced, gives fairly conclusive evidence that the ner\^e causes 

 secretion by compression of the ducts and alveoli. If these are 

 filled with an unusually large amount of fluid saliva an unusu- 

 ally large secretion, characterized by its short latent period and 

 watery character, is secreted. If there be little saliva present, 

 or if it be very viscous, we obtain a small secretion of long latent 

 period and lasting for some time. 



id) Paralysis of the Sympathetic by Emptying the Ducts 



AND ITS ReSTORAL TO PoWER BY INJECTION OF 



Fluid into the Ducts. 



Further strong evidence of the muscular action of the sympa- 

 thetic may be obtained by preventing the passage of fluid into the 

 gland and stimulating the nerve until all available saliva in the 

 ducts has presumably been expelled. The nerve then appears 

 to have lost its action, but it may be shown to be still active by 

 the injection of fluid into the ducts. The passage of fluid into 

 the gland may be prevented either by the use of quinine or by 

 compression of the gland artery. 



Heidenhain * showed that if quinine sulphate be injected into 

 Wharton's duct the secretory action of the chorda is ultimately 

 paralyzed, but the gland becomes oedematous. This indicates 

 that, although liquid is present in the lymph spaces, it is pre- 

 vented in some way from passing through the cell. If, after 

 paralysis of the chorda, the sympathetic be stimulated, a copious 

 secretion is obtained. After a few stimulations, however, the 

 nerve appears to be paralyzed. If that paralysis is only apparent, 

 due to the emptiness of the gland's ducts, we should be able to 

 obtain a secretion on sympathetic stimulation, by the injection 

 into the duct of more quinine sulphate. The following experi- 

 ment proves this to be the case. 



* Heidenhain, Studien aus Bre.slau, IV, 1868. 



