77© 



Journal of Agricultural Research 



Vol. XX, No. 10 



combination, the latter will remain nearly constant in amount and equal 

 amounts of starch will be hydrolyzed in equal times, the curve being a 

 straight line. On trie other hand, when the concentration of the starch 

 has been greatly reduced, the amount of the combination and accordingly 

 the hydrolysis will follow more closely the law of "mass action." Similar 

 results were obtained by Armstrong working with lactose, maltose, and 

 emulsin. Other investigators have found various factors influencing the 

 reaction between the enzym concerned and the substrate. For a full 

 consideration of the theory involved in "mass action" the reader is 

 referred to a discussion of the subject by Bayliss (2). 



The data submitted in Table VI are the results of a considerable number 

 of experiments which were varied to suit the requirements of the problem. 

 In the first series of experiments the amount of enzym power (0.25 gm.) 

 was constant and the volume of the starch paste solution was varied. The 

 time of hydrolysis was 19 hours at 32 C. 



Table VI. — Total amount of reducing sugars and reducing sugars per 10 cc. of solution 

 in different volumes of a 0.5 per cent starch paste solution 



In sample a the reducing sugars per 10 cc. is considerably larger than in 

 sample d, while b and c are about the same. In total reducing sugars 

 found there is a progressive increase up to and including 150 cc, and then 

 a slight decrease. While in sample a some starch yet remained nonhydro- 

 lyzed, it is likely that on approaching the end point the rate of hydro- 

 lysis was slowed up. It is probable that a shorter period of hydrolysis 

 would have given a different curve and that the total reducing sugars 

 formed would have paralleled the reducing sugars per 10 cc. 



Somewhat similar results were obtained when the total volume of solu- 

 tion (100 cc.) and the amount of enzym powder (0.25 gm.) were constant 

 but the quantity of starch paste was varied. A 1.5 per cent starch paste 

 solution was used in the dilutions, enough distilled water being added to 

 make a total volume of 100 cc. 



The time of hydrolysis was 19 hours at 32 C. The average results of 

 parallel tests are shown in Table VII. 



The results show an increase in reducing sugars with the increase in the 

 amount of starch present from sample a to sample c, inclusive, and then 

 a slight decrease. In sample a, although the end point had been more 

 closely approached than in any of the other samples, some starch still re- 

 mained unhydrolyzed . If it were not for the results obtained in samples d 



