Vol.. 7, 1921 
CHEMISTRY: SHERMAN, ET AL. 
281 
which the diet, alone or with such antiscorbutic addenda as have been 
introduced, has afforded the animal. 
Effect of Heating in Acid Solution. — In the case of tomato juice of natural 
acidity, pH = 4.3, it was found that boiling for one hour destroyed 
practically 50 %, and for four hours destroyed practically 68 % of the 
antiscorbutic vitamin present. The time curve of the destructive process 
is, therefore, much flatter than that of a unimolecular reaction or of a 
reaction proceeding according to the square root rule of Schiitz. Similar 
flattening of the time curves of the destruction of the vitamin were found 
also in experiments in which the tomato juice was heated at temperatures 
lower than boiling, viz., at 60° and at 80°. Comparisons of the data 
obtained at 60°, 80° and 100° show relatively low temperature coeffi- 
cients: Qio (60°-80°) = 1.23; Qi 0 (80°-100°) = 1.12. 
Effect of Reduced Concentration of Hydrogen Ions. — In experiments in 
which the natural acidity of the standard tomato juice was first neutral- 
ized in whole or in part, the juice then boiled for one hour and immediately 
cooled and reacidified, it was found that at pH 5.1 to 4.9 (natural acidity 
less than half neutralized) the destruction during one hour's boiling was 
increased to 58 %. Neutralization of a larger proportion of the natural 
acidity increased the rate of destruction of the vitamin. When alkali 
was added to an initial pH of 11, which fell to about 9 during the hour of 
heating, the destruction found by feeding of the juice thus treated but 
immediately cooled and reacidified, was about 65%. 
In all of these experiments the heating was performed in cotton-stop- 
pered, narrow-necked flasks from which air was probably very largely dis- 
placed by water vapor early in the heating. When the experiments upon 
heating at 100° were repeated with oxygen bubbling through the solution 
the destruction of the vitamin was much more rapid. 
Heating at 100° for one hour at pH = 11 to 9 as described above 
followed by standing for one to five days in stoppered but only partially 
filled bottles in a refrigerator at 10° C. at an alkalinity of only pH = 9 
was found to destroy 90 to 95% of the antiscorbutic vitamin, as compared 
wth 65 per cent when the solution was re-acidified after heating. This 
confirms the observations of Harden and of Hess upon the susceptibility 
of this vitamin to alkalinity even at low temperatures. 
Thus while the great instability of the antiscorbutic vitamin makes 
it an unpromising material for attempts at actual isolation, the develop- 
ment of methods for its quantitative measurement makes possible the 
study of its chemical behavior. 
1 Hess, A. F., Scurvy Past and Present, Philadelphia, 1920. 
2 Cohen, B. and Mendel, L. B., Biol. Chem., 35, 1918 (425). 
8 Givens, M. A. and McCluggage, H. B., Ibid., 37, 1919 (255). 
4 Chick, H., Hume, E. M., Delf, EM. and others; A series of papers in Biochem. J., 
1918, et seq. 
