196 Breidahl and Rothera : 



Experiment 3. (Tubes each contained 10 c.c. of mixture.) 

 Usinof malt diastase. 



Altliougli the acid and staix-li solutions were mixed before add- 

 ing to the dia.stase, the concentrations of tannic acid were strong- 

 enough to cause a precipitate to form in the diastase solution. 

 (This Avas //of the case with taka diastase in Experiment 1.) 



In 12 minutes the control a was well into the red, while the 

 olhe)-8 were all ))hR'. In 20 minutes d was beginning to show 

 traces of violet, the others being still l)lue. 



The effect on saliva was parallel, a precipitate being formed br 

 .025% of tannic acid. 



Experiment J/. (Tuljes each contained lO c.c. of mixture.) 

 This was done with weak taka diastase. 



These were left in a water bath overnight. The temperature- 

 started at 40OC.. but fell to 36oC. during the night. 



On te.sting, after 18.\ hours, the control a liad finished, d gare 

 a very slig\ht colour, r gave more colour (red), whilst h gave a 

 very red l)rown. 



In this experiment, ctnicentrations of tannic aiid, which gave 

 an acceleration in the short expei-iments. heio gave a very definite 

 retardation. 



The following experiments were done to determine whether this 

 retardation was due to actiiui (ni the ferment oi- on the starch. 



Experiment 5. (Tubes eath contained 10 c.c. of mixture.) 



Taka Diastase Tannic Acid 



(-2.,%). (final concentration). 



