547 
Enzyme of Nepenthes (//). 
given temperature. After this treatment the liquid was 
neutralized, then acidified with HC1, and a digestion-experi- 
ment was made. 
At an early stage it became apparent that the results of 
such experiments are dependent upon the three following 
factors: — (i) the degree of alkalinity; (2) the duration of 
the period of alkalinity; (3) the temperature maintained 
during the period of alkalinity. 
I took as a starting-point the statement made in my paper 
of last year (p. 572), that the digestive activity of the liquid 
is destroyed by treatment with 5 °/ o Na 2 C 0 3 for 3 hours 
at a temperature of 35-40° C. I found, on repeating the 
experiment and prolonging it, that this conclusion is not 
accurate. In the original experiment the time allowed for 
digestion was 16 J hours, and in that period, it is true, no 
trace of digestive action could be detected : but in a sub- 
sequent experiment with a longer digestive period, evident 
signs of digestion were apparent in 20 hours, and digestion 
was completed in about 26 hours. 
The following is a summary of the principal experiments 
made : — 
1 . Temperature during period of alkalinity, 35 - 38 ° C. 
Treatment with 0-5 °/ Q Na 2 C0 3 for 30 minutes ; retards digestion. 
1 % 
3 3 33 2 2 
hours ; about doubles time of 
digestion. 
» 1 % 
33 3 3 *7 
,, digestion much retarded. 
2 % 
3 3 3 3 ^ 
33 33 33 
„ 4% 
33 „ 2 
,, digestion complete with- 
in 20 hours. 
.. 5 °/ 0 
3, „ I 
,, digestion complete with- 
in 6 hours. 
„ 5% 
3 3 3 3 3 
,, digestion complete with- 
in 26 hours. 
It will be observed that, in all the foregoing experiments, 
digestion, though often much retarded, eventually took place. 
It still remained to ascertain under what conditions total 
destruction of digestive power could be effected by treatment 
