Nov. 15,1924 
Reaction Between Formaldehyde and Proteins 
477 
Table V.— The temperature coefficient of the reactions in formolized serums , de¬ 
termined by comparing the velocity constants of the reactions taking place in serums 
containing 1.85 per cent formaldehyde and kept at 39 0 and 29 0 C., respectively 
Serum kept at 39° C. 
Serum kept at 29° C. 
t 
X 
a-x 
ak 
X 
a-x 
ak 
0 .. .. _ . . 
0.00 
6. 00 
0.00 
6.00 
10___ 
1.98 
4. 02 
0.049 
.98 
5.02 
0.019 
20_ 
2.90 
3.10 
.047 
1.60 
4. 40 
.018 
30__ 
3.69 
2.31 
.053 
2.07 
3.93 
.017 
40_ 
4.14 
1.86 
.055 
2.33 
3. 67 
.016 
50__ 
4. 27 
1.73 
.049 
2.77 
3.23 
.017 
60_:_ 
4. 37 
1.63 
.044 
2.93 
3.07 
.016 
90_ 
4. 76 
1.24 
.043 
3.37 
2.63 
.014 
120_ 
3.68 
2.32 
.012 
180____ 
4.53 
1.47 
.017 
Average_ ___ . _ _ 
.048 
.016 
Coefficient_ ... __ . .. 
3.0 
1.0 
THE TITRABLE ACIDITY OF FORMO¬ 
LIZED SERUMS 
Schiff (14) found that when formal¬ 
dehyde was added to a solution of gela¬ 
tin the titrable acidity increased as 
more formaldehyde was added. He 
also added unstated amounts of formal¬ 
dehyde to albumin solutions and found 
that an immediate and relatively great 
increase in acidity was followed after 24 
hours by slight decreases. Many ob¬ 
servations upon the effect of formalde¬ 
hyde on the titrable acidity of serums 
have been made by the writer, but as 
the results of all have been in accord, 
only one will be described. 
EXPERIMENT IV 
A clear, horse-blood serum was di¬ 
vided into four portions of 100 c. c. 
each. To these four portions there was 
added, respectively, 3 ^ c. c., 1 c. c., 
3 c. c., and 6 c. c. of a formaldehyde so¬ 
lution (37.34 per cent). Samples (10 
c. c. each) were removed from each por¬ 
tion at the intervals shown in Table VI 
and titrated to a slight pink with N/10 
NaOH, using phenolphthalein as an 
indicator. 
These results show that following the 
addition of formaldehyde to a serum 
there was a rapid increase in titrable 
acidity. The speed and extent of this 
change were related to, but not pro¬ 
portional to, the amount of formalde¬ 
hyde added. The primary increase in 
titrable acidity was followed by a 
gradual decline. The observations 
were discontinued at the ninety-sixth 
hour, so the full extent of the decline 
was not determined. Identical results 
have been obtained in a number of 
other experiments. However, in one 
serum which before treatment required 
about 20 c. c. of N/10 NaOH per 100 
c. c. for neutralization, no increase in 
acidity was observed following the 
addition of formaldehyde, but only a 
constant decline. 
Table VI.— The titrable acidity of formolized serums 
N/10 NaOH required to neutralize 100 c. c. 
of serum 
Time of contact 
With y<i 
c. c. formol 
; With 1 
c. c. formol 
With 3 
c. c. formol 
With 6 
c. c. formol 
Bpfnre treatment 
C. c. 
8 
c. c. 
8 
C.c. 
8 
c. c. 
8 
3 minutes ___ __ 
19 
30 
39 
42 
15 minutes - _ 
23 
28 
| 38 
39 
1 hour _ _ 
21 
| 26 
33 
37 
3 hours - - __ _ 
13 
20 
1 25 
25 
24 hours _ _ 
9 
! n 
' 20 
20 
48 hours _ _ 
6 
I n 
! 17 
19 
96 hours - - - __ 
5 
10 
15 
18 
124 hours_ 
Gelled. 
. 
