COMPOSITION OF HUMAN MIXED SALIVA. 273 



or collected without effort, shows a natural tendency to vary 

 both in composition and in amylolytic power throughout the 

 twenty-four hours, and apparently independent of the taking 

 of food. Between 7.00 and 11.00 A.M., however, in the 

 absence of food the secretion is remarkably constant. 



Mechanical stimulation, as chewing a tasteless substance, 

 and alcohol, ether, gin, whiskey, etc., taken into the mouth, 

 all lead to the outpouring of a secretion richer in alkaline- 

 reacting salts and in amylolytic power than the secretion 

 coming without stimulation. 



Mixed saliva resulting from stimulation with ether, alcohol, 

 etc., contains a much larger proportion of mucin than the 

 secretion coming without stimulation, being noticeably thick 

 and viscid. This quality is not apparent in the saliva result- 

 ing from mechanical stimulation. 



18 



