MICHIGAN ACADEMY OF SCIENCE. 
35 
TABLE NO. 3. — Exp. No. 22. Tests Nos. 2 and 3. Sample C. 
Test. 
3. 
2 . 
3. 
3. 
2 . 
3. 
Tube. 
1 
2 
3 
2 
2 A 
2B 
4 
5 
6 
7 
S 
9 
3 A 
4 
4B 
13 
Treatment of 
solution. 
4 days 0° to S°C. 
1 day 0°- 8°C. . . 
Fresh 
6 days 0°-8°C. 
1 day 0°-S°C.. 
Fresh 
4 days 0 0 -8 C 
1 day 0°-8°. 
Fresh 
4 days 0 °-8°C . 
1 day 0°-8°C. . 
Fresh 
Fresh 
G days 0°-8°C. 
1 day 0 °-8°C . 
Fresh . 
Heating 
temper- 
ature. 
110°C 
110°C 
110°C 
110°C 
110°C 
110°C 
110°C 
110°C 
110°C 
100°C 
100°C 
100°C 
Heating 
time. 
20 Min. 
20 Min. 
20 Min. 
15 Min. 
15 Min. 
15 Min. 
10 Min. 
10 Min. 
10 Min. 
20 Min. 
20 Min. 
20 Min. 
Digestion 
hours. 
13. 
+ 
+ 
+ 
+ 
24. 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
Culture 
beef 
tea. 
Control. 
Control. 
Control. 
Control. 
Attempts to sterilize a solution of the exzyme by fractional heating at 
lower temperatures resulted iu destroying the action usually at the 
second heating. 
It was suggested by Dr. Novy that it might be possible to restore the 
vitality to a solution of the enzyme that had been killed in fresh solu- 
tion, if subsequently kept in the cold for varying lengths of time. Re- 
peated attempts in this connection show that it probably cannot be done 
so simply. 
A limited number of tests seemed to indicate that the above cold room 
treatment does not afford such protection against the action of heat on 
pepsin. 
CONCLUSIONS. 
1. Trypsin in our purest solutions, fresh, is completely destroyed 
by 80° C, at the most. 
2. Proteids and inorganic saj,ts are known to protect this enzyme 
against such heat destruction. 
3. It is believed to have been shown in this laboratory that cold, 0° 
to 8°C, will protect at least some samples of the enzyme in solution 
against extreme heat 110°C for a time of 20 min. 
REFERENCES. 
1. Biernacki — “Zeitschrift fur Biologie” ..No. 28 N. F. No. 10. 
2. Vernon — “Journal of Physiology’ * 1 2 3 4 5 6 7 8 No. 26. 
3. Vernon — “Journal of Physiology” No. 27. 
4. Vernon — “Journal of Physiology” No. 29. 
5. Bayliss & Starling— “Journal of Physiology” No. 30. 
6. Bayliss & Starling — “Journal of Physiology” No. 31. 
7. Schmidt — “H-S. Zeit. fur Physio. Chemie.” . No. 67 p. 314. 
8. Krunenberg — Biochem. Zeit No. 24. 
8. Boeder — Biochem. Zeit No. 24. 
Laboratory of Physiological Chemistry, University of Michigan, Ann 
Arbor, April, 1911. 
