ABSTRACT
I. The loss of the mucinogen component of the peptic granules begins during the fourth week of post-natal life (400 g) at a site on or near the greater curvature of the stomach adjacent to the pyloric antrum. It reaches the lesser curvature at about the sixth week (750 g).
2. The loss progresses slowly across the ventral and dorsal walls of the stomach and more rapidly along the greater curvature.
3. At 11-12 weeks (1,800 g) only a few peptic cells on the greater curvature and adjacent to the oesophageal opening contain PAS-positive granules.
4. Except for a few granules in an occasional peptic cell, no mucinogen can be demonstrated in these cells after the fourteenth week (1,900 g).
5. The stage seems to be correlated more closely with the weight than with the age of the animals.
