%2&fiST}     Method  for  Estimation  of  Pepsin.  545 
final  total  acidity  of  the  tube  containing  the  greatest  amount  of  diluted 
gastric  juice  would  never  reach  04  per  cent. 
In  a  series  of  24  observations  (Table  I)  on  normal  and  pellagrous 
individuals,  there  are  only  two  instances  in  which  a  value  has  been 
obtained  by  following  exactly  Rose's  method.  Strict  attention  has 
been  paid  to  neutralization.  Titrations  have  first  been  made  with 
alizarin  red  and  phenolphthalein.  The  first  tinge  of  brown  with 
alizarin  red  reacted  neutral  to  litmus.  In  other  instances  the  contents 
have  been  titrated  to  the  first  perceptible  tinge  of  pink  with  phenol- 
phthalein, and  then,  for  the  Rose  method,  another  sample  was  made 
neutral  to  litmus  by  stopping  short  of  this  point.  In  no  case  has  the 
reaction  been  alkaline. 
Table  I. 
Case. 
Total 
acidity. 
Free 
acidity. 
Pepsin  number. 
Proposed  Rose 
method.  method. 
Remarks. 
I 
91 
70 
50 
Trace. 
Normal. 
2 
60 
45 
41 
Trace. 
Do. 
3 
44 
21 
31 
Trace. 
Do. 
4 
61 
44 
41 
12 
Do. 
5 
83 
67 
41 
Trace. 
Do. 
-  6 
84 
69 
41 
Trace. 
Do. 
7 
61 
46 
25 
Trace. 
Do. 
8 
55 
42 
41 
Trace. 
Do. 
9 
7i 
49 
41 
Trace. 
Do. 
10 
89 
70 
40 
Trace. 
Do. 
11 
69 
49 
42 
Trace. 
Do. 
12 
5i 
26 
42 
Trace. 
Do. 
J3 
58 
42 
42 
Trace. 
Do. 
14 
7i 
53 
40 
Trace. 
Do. 
15 
78 
64 
33 
12 
Pellagra. 
16 
25 
12 
33 
Trace. 
Do. 
17 
76 
57 
41 
Trace. 
Do. 
18 
57 
38 
40 
Trace. 
Do. 
19 
45 
25 
25 
Trace. 
Do. 
20 
84 
64 
3i 
Trace. 
Do. 
21 
56 
3i 
21 
Trace. 
Do. 
22 
21 
0 
Trace. 
0 
Do. 
23 
35 
7 
12.5 
0 
Do. 
24 
14 
0 
Trace. 
0 
Do. 
No  attempt  is  made  in  this  paper  to  take  up  the  question  of  gastric 
digestion  in  pellagra. 
That  neutralization  in  the  Jacoby  method  will  in  a  like  manner 
destroy  or  inhibit  some  of  the  pepsin,  and  consequently  influence  the 
results  appears  from  the  following: 
