188 
BULLETIN OF THE BUREAU OF FISHERIES 
TRYPTIC DIGESTION 
Tables 3 and 4 show data obtained for tryptic digestion by extracts from the 
pancreas in different animals and from the hepatopancreas of the carp. The 
results are typical for tryptic digestion, a comparatively large amomit of amino 
acids being split off in addition to a large amoimt of tyrosine, while in peptic digestion 
amino acids were split off only to a very slight extent (cf. Tables 1 and 2). Since 
the experiments were carried on in definitely alkaline media having an initial pH 
above 8, peptic and autolytic digestion would be practically ruled out. That the 
digestion of egg white by extracts from the pancreas was truly tryptic was further 
shown in separate tests by the fact that as the hydrogen-ion concentration was 
increased to pH 7 and higher the rate of digestion rapidly decreased, and vice versa. 
Table 3. — Tryptic digestion in different groups of vertebrates 
[Except for Nectuxus ' and bull snake,' digests were made up of the proportion: 12.5 c. c. pancreas extract +20 c. c. coagulated egg 
albumin4-0.2 N sodium carbonate to approximately pH 8.4+toluol (10 per cent of total) +distilled water to 50 c. c. tot^ 
volume] 
Aver- 
age 
tem- 
pera- 
ture 
Milligrams tyrosine in 2 c. c. filtrate 
C. c. 0.2 N amino acid in 10 c. c. filtrate 
Animal 
Days 
Net 
Days 
Net 
in de- 
grees 
0 
1 
2 
4 
8 
gain 
0 
1 
2 
4 
8 
gain 
23 
0.143 
0.182 
0.200 
0.229 
0.250 
0.107 
0.30 
0. 45 
0.55 
0. 65 
0.80 
0.50 
Pickerel - 
23 
.317 
.431 
.455 
.591 
.650 
.333 
.35 
.50 
.90 
1.00 
1.10 
.75 
25 
.294 
.625 
.714 
.884 
.590 
.35 
2. 25 
1.90 
26 
.173 
.527 
.637 
.909 
.966 
.793 
.25 
1.36 
2. 10 
1.85 
Dog--- 
23 
.313 
.645 
.704 
.681 
.681 
.368 
.70 
1.70 
1.85 
2.00 
2. 30 
1.60 
Necturus 
23 
.190 
.303 
.400 
.435 
.245 
.30 
.50 
.75 
.90 
.60 
21 
.148 
.334 
.385 
.435 
.287 
.35 
.65 
1.00 
1. 10 
.75 
1 Necturus digest contained only 5 c. c. of extract, thus representing only 40 per cent of the amount of pancreas used in the 
' Bull snake digest contained only 4 c. c. of extract, representmg about 32 per cent of the amount of pancreas used in the first 
five tests. It was necessary to work with a much smaller quantity in Necturus and snake because of the very small amount of 
pancreas obtainable. 
Table 4. — Tryptic digestion at room temperature and at 37° C. 
[Digests were prepared exactly as in Table 3, with an initial pH approximately 8.4] 
Animal 
Tem- 
pera- 
ture 
in de- 
grees 
Milligrams tyrosine in 2 c. c. filtrate 
0. c. 0.2 N amino acid in 10 c. c. 
filtrate *; 
Days 
Net 
gain 
Days 
Net 
gain 
0 
1 
2 
4 
8 
0 
1 
2 
4 
8 
Carp (hepatopancreas) 
/ 23 
0. 100 
0. 138 
0.167 
0.182 
0. 182 
0.082 
0.20 
0.30 
0.40 
0.50 
0.55 
0.35 
\ 37 
. 100 
. 160 
.211 
.250 
.345 
.245 
.20 
.35 
.50 
.65 
.95 
.75 
Do. - ---- 
/ 23 
.143 
. 182 
.200 
.229 
.2.50 
. 107 
.30 
.45 
.55 
.65 
.80 
.50 
\ 37 
.143 
.211 
.235 
.385 
.455 
.312 
.30 
.65 
.65 
.90 
1. 10 
.80 
/ 23 
.313 
.645 
.704 
.681 
.681 
.368 
.70 
1.70 
1. 85 
2.00 
2.30 
1.60 
\ 37 
.313 
.695 
.741 
.695 
.695 
.382 
.70 
2. 10 
2.30 
2.40 
2.40 
1.70 
Necturus (pancreas)' --- 
/ 23 
.190 
.303 
.400 
.435 
.245 
.30 
.50 
.75 
.90 
.60 
. 160 
.476 
.527 
.527 
.367 
.30 
.70 
1. 10 
1. 40 
1. 10 
I 37 
> Necturus digest contained only 5 c. c. of extract. 
