Ad  VJmberPi9ai4m' }  Standardization  of  Commercial  Papain. 
547 
Calculate  the  percentage  of  protein  digested  under  these  con- 
ditions. 
Tryptophane  Test  No.  i. — 5  c.c.  of  5  per  cent.  Witte's  peptone 
in  1  per  cent,  salt  solution,  5  c.c.  of  1  per  cent,  papain  extract  in  1 
per  cent,  salt  solution  (toluene,  1  drop).  Add  1.2  c.c.  1.71  per  cent. 
HCN  solution,  and  1.2  c.c.  N/10  hydrochloric  acid;  total  volume, 
12.4  c.c.  Digest  in  glass-stoppered  bottles  for  17  hours  at  360  to 
400  C.    Add  bromine  water  drop  by  drop. 
Tryptophane  Test  No.  2. — 5  c.c.  of  5  per  cent.  Witte's  peptone 
digested  with  5  c.c.  1  per  cent,  papain  solution  and  1  c.c.  HCN 
(1.71  per  cent.)  at  8o°  C.  for  15  minutes  should  give  a  strong 
tryptophane  test  with  bromine  water.  Report  the  intensity  of  the 
color  in  the  following  comparative  terms :  Faint,  distinct,  marked, 
strong,  deep. 
Examination  of  Fictitious  Sample. — An  apparently  fraudulent 
sample  gave  the  following  analytical  results :  Digestion  at  80 0  C, 
none;  at  360  to  400  C.  in  0.2  per  cent,  hydrochloric  acid,  61.0  per 
cent,  and  63.0  per  cent. ;  at  360  to  400  C,  at  the  alkalinity  of  egg, 
Table  I. 
Examination  of  Samples  of  Dried  Pawpaw  Latex  Containing  no  Diluents. 
Laboratory  No  
3035 
3044 
304S 
3ii7 
3039 
3040 
3328 
Digestion  at  8o°  C,  blank. 
0.424 
0.174 
58.9 
0.417 
0.236 
43-4 
0.417 
0.228 
45'- 3 
0.403 
0.169 
58.1 
0.407 
0.180 
55-7 
0.407 
0.193 
52.1 
0.394 
0.165 
58.1 
Digestion  at  360  to  400  C.  : 
(a)  0.2  per  cent.  HC1, 
blank  
Residue  
Per  cent,  digested  
0.421 
0.433 
None 
0.417 
0.407 
'  2.4 
0.434 
0.432 
None 
0.429 
0.421 
1.8 
0-439 
0.426 
2.9 
o.434 
0.431  1 
None 
0.414 
0.424 
None 
(b)   Alkalinity  of  egg, 
blank  
Residue  
Per  cent,  digested  
0.436 
0.418 
4.1 
0.417 
0.401 
3-7 
0.427 
0.406 
2.6 
0.410 
0.405 
1.2 
0.425 
0.419 
1.4 
0.421 
0.423 
None 
0.432 
0.433 
None 
(c)  0.5  per  cent.  Na2C03, 
Per  cent,  digested  
0.435 
0.434 
None 
0.416 
0.432 
None 
0.427 
0.433 
None 
0.410 
0.413 
None 
0.425 
0.430 
None 
0.421 
0.436 
None 
0.414 
0.417 
None 
Tryptophane  test,  400  C. . 
Tryptophane  test,  8o°  C. 
Nitrogen  
Starch  
Ash  
Sugars,  reducing  
Sugars,  non-reducing  
Strong 
Deep 
9.51 
None 
6.56 
10.13 
None 
None 
Deep 
Marked 
9.87 
None 
7.13 
11.23 
None 
None 
Strong 
Strong 
9.87 
None 
7-33 
11. 12 
None 
None 
Strong 
Strong 
9.98 
None 
7.38 
11.50 
None 
None 
Strong 
Marked 
9-59 
None 
9.21 
9.28 
None 
None 
Strong 
Strong 
9,88 
None 
10. 11 
9.62 
None 
None 
Strong 
Marked 
9.89 
None 
13.87 
5.10 
None 
None 
