^S^mbeV^i™'}  Standardization  of  Commercial  Papain. 
549 
there  was  no  digestion,  and  the  same  result  was  obtained  when  the 
digestion  was  carried  out  in  a  medium  of  0.5  per  cent.  Na2Co3.  It 
gave  negative  tryptophane  tests  under  both  conditions.  Nitrogen, 
Table  III. 
Examination  of  Papain  Samples  Containing  Sugar  as  Diluent. 
3118 
3037 
3083 
0.400 
0.274 
3i.5 
0.399 
0.298 
25-3 
0.421 
0.327 
22.3 
Digestion  at  360  to  400  C: 
(ot)  0.2  per  cent.  HC1,  blank. .  . 
0.214 
49-3 
0.215 
47-2 
0.216 
47-0 
(b)  Alkalinity  of  egg,  blank..  .  . 
O.428 
0.422 
1.4 
0.407 
0.401 
1-5 
0.438 
0.435 
None 
(c)  0.2  per  cent.  Na2C03,  blank 
Residue  
O.428 
O.423 
1.0 
0.408 
0.410 
None 
0-439 
0.440 
None 
Per  cent,  digested  
Tryptophane  test,  400  C  
Tryptophane  test,  8o°  C  
Distinct 
Faint 
5-79 
None 
4.14 
9-95 
24-75 
Marked 
Faint 
6.15 
None 
4.11 
24.5 
Distinct 
Faint 
5-8i 
None 
4.21 
25.65 
Ash  
1  Calculated  as  lactose. 
1.3  per  cent,  and  1.34  per  cent.;  starch,  none ;  moisture,  9.59  per 
cent. ;  ash,  4.05  per  cent.  Reducing  sugar  was  determined  after  in- 
version with  hydrochloric  acid,  and  when  calculated  as  glucose 
amounted  to  73.75  per  cent. 
SUMMARY. 
1.  In  these  digestions  with  pawpaw  juice  it  has  again  been  shown 
that  the  digestion  proceeds  rapidly  at  8o°  to  ioo°  C.  This  character- 
istic property  can  be  utilized  for  the  standardization  of  commercial 
papain  samples. 
2.  Under  the  conditions  outlined  above,  dried  pawpaw  juice 
should  be  capable  of  dissolving  at  8o°  to  ioo°  C.  not  less  than  40  per 
cent,  of  the  egg-albumin  taken. 
3.  No  samples  of  "papain"  were  found  upon  the  market  which 
had  a  higher  digestive  activity  than  the  samples  of  dried  pawpaw 
latex  under  the  conditions  employed. 
