Reaction of white and yolk during incubation. Die Reaktion verschiedener Komponenten in den Hühner- und Enteneiern im Zusammenhang mit dem Stoffwechsel des Embryos während der Brut. N. M. Schkljar. Archiv für Geflügelkunde, Vol. 10, 1936, No.1.

1. 1. In the first 3–4 days of incubation the alcalinity of the white increases; afterwards alcalinity decreases again, but not down to neutral.

2. 2. The yolk shows a slightly acid reaction at the start; at the termination of the incubation the reaction becomes fairly alcaline.

3. 3. The pH of the amnionliquid varies during incubation, never becoming more than slightly alcaline.

4. 4. In the beginning this liquid is alkaline (pH > 8). From the 16th day the reaction becomes acid, and in our investigations it reached a pH of 5.632 at hatching time.

5. 5. The pH differs in different organs of the embryo, during its development the different organs become more and more acid in different degress. This increase in acidity is most striking in the glandular part of the stomach.

6. 6. The acid reaction of the stomachcontent becomes pronounced in the last days of embryonic life, expressing itself in a progressive of H-ion concentration.