Amylolytic Activity of Human Saliva. 



19 



of 20 per cent, sodium carbonate are added and the tube placed 

 in boiling water for 15 to 20 minutes. It is then allowed to cool and 

 diluted with distilled water in an accurately graduated cylinder 

 until the intensity of the color approximates that of the standard 

 (glucose in picric acid treated with sodium carbonate and heated), 

 after which it is compared with the standard in the colorimeter. 

 After correcting for the reducing power of the soluble starch, the 

 activity is recorded in terms of the percentage of starch converted 

 to reducing sugar. 



Utilizing the principles outlined above it has been found pos- 

 sible to obtain a demonstrable amylolytic activity at a dilution 

 of 1 to 400 when water was used as the diluent, and at 1 to 2,000 

 when dilution was made with 0.3 per cent, sodium chloride. For 

 purposes of comparison a dilution of 1 to 100 (actually 1 to 200 

 allowing for the starch solution) appears to be the most suitable, 

 with distilled water as the diluent. Although 0.3 per cent, so- 

 dium chloride is an excellent activator and represents the approxi- 

 mate content of sodium chloride in saliva, nevertheless with the 

 handicap of a low chloride content, it appears possible to bring 

 out greater individual variations than is possible otherwise. It 

 may be noted that, with the dilutions employed, the variations 

 do not appear to be influenced by the native content of sodium 

 chloride in the saliva. 



The method has been applied to a considerable number of nor- 

 mal individuals, the activity in the majority of cases falling be- 

 tween 30 and 45 when water was used as the diluent. With so- 

 dium chloride the variations were small, most of the figures falling 

 between 46 and 50, suggesting the possibility that in some indi- 

 viduals a considerable part of the ferment is secreted in the zy- 

 mogen form. Figures obtained on the same individuals at the 

 same time of day agree very closely. The activity has been tested 

 on representatives of a number of different nationalities and found 

 to vary within essentially the same range as above. The same 

 was true of a number of pathological cases including such con- 

 ditions as diabetes, nephritis, gastric ulcer, etc. Several indi- 

 viduals were encountered, however, who for periods showed low 

 activities, figures 10 to 20. Some of these had persistently suf- 

 fered from gastric distress, others were suffering from acute in- 



