Surface Tension and Ferment Action. 



581 



Experiment F. 16.5.14. Invertase Preparation same as in Previous 



Experiment. 



Kept for 25 hours at 41°, (1) in contact with beads; (2) alone as control. 

 1 c.c. of each added to 10 c.c. sucrose solution, 9'6 per cent. Digested 

 at 18°. 



Hours. 



Contact invertase. 



Control invertase. 







+ 5 79 



+ 5-70 



19 



+ 2-92 



+ 1-99 



42 



+ 0-44 



-0-52 



It will be noted that there is a marked effect in both cases, and that with the 

 longer exposure of the ferment to the beads, the disappearance of the ferment 

 becomes more marked. 



The effect of temperature will be seen from the following experiment : — 



Experiment G. 7.7.14. Invertase D, 30.6.14. 



Kept for 22 hours, (1) in contact with beads at 18°, 29°, and 40°, and (2) alone 

 as control at the same temperature. 1 c.c. of each of the six ferment 

 solutions added to 10 c.c. of sucrose solution, 9 per cent. Digested at 30°. 





18 c . 



29°. 



40°. 



Hours. 



Contact 

 invertase. 



Control. 



Contact 

 invertase. 



Control. 



Contact 

 invertase. 



Control. 







+ 5-99 



+ 5-99 



+ 5-99 



+ 5-99 



+ 5'99 



+ 5-99 



26£ 



+ 2-73 



+ 1-79 



+ 2 -37* 



+ 1 -67* 



+ 4 -44f 



+ 3 -74f 



* Examined half an hour later than tubes kept at 18°. 

 f Examined one hour later than tubes kept at 18°. 



This experiment is of interest because it shows, in addition to the dis- 

 appearance of invertase owing to adsorption, a destruction of the ferment even 

 in the control at higher temperatures (40°). This destructive effect is 

 apparently enhanced by increasing the surface. This effect would explain 

 the results obtained in Experiment C (15.6.14), where there was not only 

 an almost complete inhibition of the action of the ferment, but where this 

 inhibition persisted even after the factor of surface energy was again removed. 



The experiments just quoted, which were carried out with two different 

 preparations of invertase, gave a distinctly positive result with reference to 



