i6 
Note  on  Lactic  Acid. 
( Am.  Jour.  Bharm. 
\    January,  1911. 
contaminated  with  the  carbon  dioxide  which  is  given  off  by  the 
flame  of  the  burner,  the  boihng  was  effected  in  Erlenmeyer  flasks 
which  were  fitted  with  india-rubber  sHt  valves  (Bunsen's  valve). 
Eight  samples  of  lactic  acid  were  examined,  the  solution  of  each 
being  also  titrated  directly  at  ordinary  temperature  (designated  as 
procedure  No.  i  in  the  Tables).  Seven  of  these  samples  were 
obtained  from  American  firms,  while  one  was  obtained  from  a  Ger- 
man firm  (Kahlbaum).  The  results  obtained  are  given  in  the 
following  tables : 
TABLE  I. 
Shozving  Lactic  Acid  Strength  of  Various  Commercial  Samples  of 
Lactic  Acid  as  Determined  by  Various  Procedures. 
Amount  of 
N/io  NaOH 
Lactic  acid 
No.  of 
No.  of 
lactic  acid  so- 
added before 
N/io  NaOH 
strength  of 
sample. 
procedure 
lution  taken. 3 
titration. 
required. 
sample. 
(c.c.) 
(c.c.) 
(c  c.) 
J 
20 
0 
TO  nC 
72  \A 
r\ 
\J 
0  T  rv~» 
3 
r\ 
U 
o5o9 
4 
87  67 
5 
20 
40 
23.15 
87.67 
2 
I 
20 
0 
18.30 
71.95 
2 
2 
20 
0 
21.10 
82.95 
2 
3 
20 
0 
2T.9O 
86.10 
2 
4 
20 
40 
22.45 
88.26 
2 
5 
20 
40 
22.55 
88.65 
3 
I 
20 
0 
18.05 
71.86 
3 
2 
20 
0 
21.00 
83.63 
3 
3 
20 
0 
21.60 
85.99 
3 
4 
20 
40 
22.40 
89.18 
3 
5 
20 
40 
22.40 
89.18 
4 
I 
20 
0 
18.40 
71.72 
4 
2 
20 
0 
21.25 
82.83 
4 
3 
20 
0 
22.00 
85.75 
4 
4 
20 
40 
22.60 
•88.10 
4 
5 
20 
40 
22.70 
88.48 
*The  solutions  of  lactic  acid  used  contained  the  following  amounts  in 
grammes  of  the  respective  samples  of  lactic  acid  in  1000  c.c.  of  the  solution : 
No.  I,  11.8825;  No.  2,  11.4463;  No.  3,  IL3034;  No.  4,  11.5446;  No.  5,  11.7030; 
No.  6,  IL6975;  No.  7,  IL5736;  No.  8,  11.5892. 
