Diurnal Changes in the Acidity of Bryophyllum Calycinum

1. It has been shown that there is a diurnal change in the H ion concentration in Bryophyllum calycinum corresponding approximately to the total acidity changes. The H ion concentration increases at night and decreases during the day. 2. Light is the main factor in causing the decrease in acidity, though it also occurs in the dark. but much more slowly. 3. External oxygen tension does not seem to influence the acidity of the plant, nor does it influence the decomposition of the extracted juice.