476 
Journal of Agricultural Research 
Vol. XXIX, No. 10 
Table IV.— The temperature coefficient of the reactions taking place in formolized 
serums as determined by comparing the times required for a given amount of work 
to be done in serums containing 1.85 per cent of formaldehyde and kept at 29° and 
39° C., respectively 
M//vtrr£& 
Fig. 2—The rate of reaction in serums containing 1.85 per cent formaldehyde and kept at 29° and 39° C., 
respectively 
An inspection of these results shows 
that the temperature coefficient of this 
reaction was approximately 3. This 
relatively high temperature coefficient 
eliminates the possibility of mere physi¬ 
cal changes being responsible for the 
alteration in solubility brought about 
in serum proteins by the addition of 
formaldehyde, since the temperature 
coefficients of physical reactions are 
less than 2 (13, p. 216). 
It is believed that the foregoing 
results show that the reaction in this 
experiment had a temperature coeffi¬ 
cient of 3. However, in order to deter¬ 
mine whether the same temperature co¬ 
efficient could be obtained by comparing 
the velocity constants of the two reac¬ 
tions, the values for these were calcu¬ 
lated by the use of the bimolecular for¬ 
mula in the manner previously described. 
The results are shown in Table V. 
It will be noted in Table V that 
fairly constant values for ak were ob¬ 
tained for both serums, and that the 
value for ak obtained in the case of the. 
serum kept at 39° C. is three times as 
great as for the serum kept at 29°. 
Thus by this method a temperature 
coefficient of 3 is also shown. 6 
6 The serum upon which Table III is based and the serum shown in Table V as having been held at 29° C. 
both contained the same amount of protein and were held at about the same temperature. The two serums 
contained different amounts of formaldehyde; nevertheless, velocity constants, although not identical, were 
very similar. This suggests that the rate of reaction in formolized serums, provided an excess of the alde¬ 
hyde is present, depends more upon the concentration of the proteins than upon that of the formaldehyde. 
There is also a suggestion that the formaldehyde itself does not enter the reaction of which the velocity con¬ 
stant was determined. These suggestions are in harmony with the observation that the addition of for¬ 
maldehyde in excess may retard the rate of gratification of serums. 
