803 
then, that phosphate-mixtures are inhibitive to the action; less so in 
highly dilute than in the concentrated solutions. 
2. Experiments with citrate-mixtures. A citrate solution was made 
from 275 gr. of pure citric acid (pro analysi), 105 gr. of NaOH 
(MrrcK’s e natrio pro analysi) and water to 1 liter. 20 e.c. of this 
citrate solution diluted with water to 250 ee. yielded py= 4.915. 
4th Series of experiments. Enzyme R. 
7 | | - — AS Gi | a A 
Citrate NaOH H,O Amy- En- BE Rotation, | 
Nr. solution | | lum (zyme! „Gr lodine reaction <p}, 
ALE BE | Beijen | GT. C minutes, 
u 
| | | | | acres | | 
he 10 | 14.7 (25.3 | 200 2 247.60 195 bluish-violet 5.99 
2| 10 | 19.5720.43 200 | 2 | 357.15 189 | reddish-violet 6.49 
| | | 
3 10 | 19.94 20.06 200 2 380.15 189 red, shade of violet 6.526 
| | | 
4 10 20.40 19.6 | 200 2 380.65 « 188 reddish-brown 6.62 
| | | 
5 | 10 | 21.3 [18.7 | 200 2 396.00 187 reddish-brown 6.73 
6} 10 | 22.1 17.9, 200 | 2 | 358.65 187 _ red, shade of violet 7.09 
eend 117. 0: | 200 | 2 | 183.15 | 197 blue, shade meh ee 
| | | | 
sth Series of experiments. Enzyme R diluted with 1 vol. of water. 
= | ] a a = : ee a —— 
Citrate NaOH HO | Amy-, En- ta à Rotation, 
Nr.| solution ‚lum | zyme) 4 Gr lodine reaction | Pu 
Cc EG on Eee LEE | Cars ‚minutes | 
| | cal 
| | | | | 
Rensen cole AO) 200 le Be BT 3B.) 200,7} blue 5.80 
| | | | | | 
2 | 2 | 8.20 136.6 .|=,200- |. 2 139.70 | 200 | blue ‚6.26 
3) 5 | 9.78 |35.22; 200 2 | 158.10 197 \blue,shade of violet 6.55 
| | | | | 
4 | 5 10.20 (34.80) 200; 2 | 147.85 | 199.3 blue, shade of violet 6.74 
| | | | | 
5 | 5 10.65 34.35, 200 | 2 [28:45 |= ‘201 blue 6.85 
| | | | 
6 | 5 10.90 |34.10) 200 | 2 1071957120800" blue (1.046 
| | | | 
TS 11.05 33.95) 200 | 2 | 90.05 | 204 | blue 7.11 
8| 5 _ |11.30}33.70| 200) 2 | 60.90] 204.5 | blue 7.41 
9) 5 mops -200) 2 secon 205 blue 7.497 
Here again an optimal reaction is educed, which, however, has 
slightly shifted towards the neutral point. A decrease of concentra- 
tion diminishes this deviation, 
