The Physiological Basis of Thirst. 



297 



A similar diminution of the salivary secretion occurs after the loss of 

 water from the body by sweating. In one instance, the loss in about one hour 



C.C 



15i 



HOUR 



Fig. 1. — Chart showiug saliva secreted each hour from 7 a.m. until 8 p.m. in consequence 

 of chewing a tasteless gum five minutes. No fluid was drunk between 7 o'clock 

 the previous evening and 3 o'clock p.m. For further description, see text. 



of approximately 500 c.c. of body fluid as sweat was accompanied by a reduc- 

 tion in the salivary output of almost 50 per cent. 



Corresponding to the diminution of the salivary output as the result of 

 chewing was a diminution in the reflex flow as a consequence of letting the 

 mouth become dry. The reflex flow has fallen, in my experience, from 

 3 or 4 c.c. in five minutes under normal conditions to a little more than 

 1 c.c. during thirst. 



