270 



AMYLOLYTIC POWER AND CHEMICAL 



not be connected primarily with any specific stimulation of 

 metabolic or secretory activity. 



However this may be, it is quite clear that the natural 

 variations in the character of the mixed saliva, indicated by 

 the results of the last four experiments of the above series, 

 render it necessary to use great caution in arranging the con- 

 ditions under which the experiments are tried. We have 

 therefore repeated the above experiments, choosing for the 

 collection of the saliva a time of day when we have found the 

 mixed saliva most constant in composition, viz., between 9.30 

 and 10.30 A. M. To be sure, there are variations in the com- 

 position and starch-digesting power of successive portions of 

 saliva collected by the same method at this period, but they 

 are relatively small, quite small, indeed, as compared with 

 the variations liable to occur at other periods of the day. The 

 truth of this statement is illustrated by the two following 

 experiments, in which the saliva was collected without stimula- 

 tion, simply allowing it to flow from the mouth. 



Thus, the two portions collected between 9.32 and 10.42 

 A.M. are essentially alike, while the two fractions secreted 

 between 5.00 and 5.50 P.M., all without stimulation, are more 

 dissimilar. Adopting the morning hour as the better time for 

 collection, experiments were tried with alcohol, ether, chloro- 

 form, whiskey, and gin, comparing in each case the saliva 

 obtained under their influence with the secretion coming with- 

 out stimulation of any kind. The exact method pursued in 

 the case of the control, t. e. t with water, was to rinse the 



