The tuberculin reaction and anaphylaxis as studied by the Dale method
Experimental biology and medicine
immediately cooled and reacidified, it was found at Pn 5.1 to 4.9 (natural acidity less than half neutralized) the destruction during one hour's boiling was increased to 58 per cent. Neutralization of a larger proportion of the natural acidity regularly increased the rate of destruction of the vitamine a t 100'. When alkali was added to an initial PH of I I , which fell to about 9 during the hour of heating, the destruction found by feeding of the juice thus treated but immediately cooled and
... iately cooled and reacidified, was about 65 per cent. On repetition of the last mentioned experiments but with reacidification omitted, and the treated juice stored up to five days in the refrigerator before feeding, the destruction found was 90 to 95 per cent. Whether the difference between the juices which were, and those which were not, reacidified is attributable wholly to the prolonged action of the hydroxyl ions a t a temperature of 10' C., and PH only 9, or whether there are here involved other factors possibly including a tendency toward reversal of the destructive process upon reacidification, remains to be determined. The tuberculin reaction and anaphylaxis as studied by the Dale method.