126 Chittenden and Martin—Influence of Temperature on the 
Hiippe* likewise, has made a study of the effect of high tempera- 
tures on the two ferments, in manner similar to the experiments of 
Bull, Hiifner and Salkowski, not, however, to ascertain the effects of 
definite temperatures on ferment action, but rather to ascertain the 
extent to which the dry ferments can be heated without destroying 
their peculiar properties, 
It has been our purpose to obtain by quantitative methods, definite 
expressions of the influence of temperature on the relative amylolytic 
action of the two ferments. 
Our method of determining amylolytic action, is based upon the 
gravimetric determination of the cupric oxide-reducing power of the 
solution, resulting from the action of the ferment upon starch paste, 
according to the method of Allihn.t This gives very concise and 
definite results of admitted accuracy. The cupric oxide-reducing 
power of a solution, resulting from the amylolytic action of these two 
ferments, must necessarily express the degree of intensity of ferment 
action, since the more energetic the action, the larger the amount of 
sugar (maltose and dextrose) formed, with higher reducing power; 
while the weaker the action, the larger the amount of dextrins 
with lower reducing power. 
The amylaceous material employed in the experiments, was purified 
corn starch. In each experiment 1 gram of the starch was made into 
a paste with 50 c. c. of boiling water, then 40 c. c. more water were 
added, and lastly, when everything was in readiness, 10 ¢. ¢. of the 
ferment solution, either saliva or malt extract ; thus making a volume 
of 100 ¢, ¢. containing 1 per cent. of starch. In every case, the fer- 
ment was allowed to act upon the starch at the desired temperature 
for exactly thirty minutes, when further ferment action was at once 
stopped by the addition of a definite quantity of dilute acid. The 
ferment being thus destroyed, the solution was neutralized by adding 
an amount of sodium hydroxide equivalent to the acid, after which 
the solution was concentrated, then made up to exactly 100 ¢. ¢., and 
in 25 ¢.¢., or one-fourth of the filtered fluid, the reducing bodies were 
determined. From the weight of metallic copper so obtained, the 
reducing bodies are, for the sake of comparison, calculated as dex- 
trose, from which in turn is calculated the percentage of starch con- 
verted. Naturally the amount of starch digested, is larger than the 
figures indicate, since the reducing power of maltose and. the dex- 
trins is much smaller than that of dextrose, but the above method 
of calculation is most convenient and for comparison quite sufficient. 
* Jahresbericht fiir Thierchemie, 1881, p. 446. Ueber das Verhalten ungeformter 
Fermente gegen hohe Temperaturen. 
+ Zeitschrift fiir Analytische Chemie, xxii, p. 448. 
