i8 



Scientific Proceedings (94). 



higher plants and fungi respectively. Laboratory methods for 

 the purification of each of these amylases have been described in 

 previous papers. The present experiments were performed with 

 enzyme preparations which had been purified in accordance with 

 these methods. The experiments establish for each of the three 

 amylases the limits of hydrogen ion concentration within which 

 any enzymic activity is shown, and the form of the curve repre- 

 senting the activities at all concentrations of hydrogen ion be- 

 tween these limits. The investigation was carried out with the 

 aid of a grant from the Carnegie Institution of Washington. 



13 (1388) 



Studies on the amylolytic activity of human saliva with a new 



method. 



By Victor C. Myers and Anne G. Dellenbaugh. 



[From the Laboratory of Pathological Chemistry, New York Post- 

 Graduate Medical School and Hospital, New York.} 



Saliva is the one glandular secretion which can be readily ob- 

 tained in the human subject under relatively constant conditions, 

 and its amylolytic activity has therefore been a time-honored 

 topic of investigation. Nevertheless the methods used for esti- 

 mating this activity have been rather crude or tedious. A method 

 is described below which is simple, delicate, and, we believe, very 

 accurate. With it a large series of comparable figures may read- 

 ily be obtained. The method is similar to that which has been 

 employed here in estimating the diastatic activity of the blood. 1 



The technique is as follows: A specimen of mixed saliva, ob- 

 tained by the stimulation of paraffin chewing, is filtered and a 

 small portion accurately diluted 1 to 100 with distilled water, and 

 also another portion with 0.3 per cent, sodium chloride as an ac- 

 tivating solution. After thorough mixing 1 c.c. of the diluted 

 saliva is pipetted into a test-tube and the tube placed in a water 

 bath at 40 0 . After 5 minutes 1 c.c. of 1 per cent, soluble starch solu- 

 tion is added and the mixture allowed to incubate for 30 minutes. 

 At the end of this time 3 c.c. of saturated picric solution and 1 c.c. 



1 Myers and Killian, Jour. Biol. Chem., 1917, xxix., 179. 



