VARIATIONS IN THE AMYLOLYTIC POWER 



AND CHEMICAL COMPOSITION OF 



HUMAN MIXED SALIVA.* 



BY B. H. CHITTENDEN AND A. N. BICHARDS. 



SINCE saliva is the product of secretory glands having their 

 periods of comparative rest and activity, it follows quite nat- 

 urally that this secretion might be expected to show variations 

 in amylolytic power at different periods of the day : i. e., that 

 the secretion obtained after a period of glandular activity 

 might possess less starch-digesting power than the secretion 

 coming from glands which have been in a state of rest due 

 mainly to variations in the proportion of active enzyme pres- 

 ent. Further, the well-known sensitiveness of the amylolytic 

 enzyme to changes of reaction suggests also the possibility of 

 fluctuations in amylolytic power dependent primarily upon 

 changes in the proportion of alkaline-reacting salts contained 

 in the secretion. In spite of the large amount of work of a 

 chemico-physiological nature done upon saliva, these questions 

 have received very little attention. During the past year, 

 however, Hofbauer,f in an interesting communication has pre- 

 sented a series of results, bearing on the daily fluctuations in 

 the amylolytic power of saliva, but his observations were 

 limited solely to determination of the starch-digesting power 

 at different periods of the day without regard to any possible 

 relationship between the amylolytic power and the chemical 

 composition of the secretion. His results, however, show 



* Beprinted from Amer. Joura. Physiol., vol. i. A summary of some of 

 the results contained in this paper was presented at the meeting of the 

 American Physiological Society in December, 1897, and published in the 

 Proceedings of the Society, Amer. Journ. Physiol., 1898, ii, p. iii. 



t Hofbauer, Archiv f . d. gea. Physiol., 1897, IXT, p. 603. 



