The duodenum, jejunum, ileum and large intestine of newborn, and 24-hour-old fed and unfed piglets, and of 10-day-old piglets have been studied by new histochemical methods. At birth Meissner’s plexus was most developed in the duodenum. There was little change during the first 24 h, but by 10 days it had become elaborated. Goblet cells were present at birth in all parts of the intestine. After 24 h a large proportion of those in the duodenum had discharged and were being replaced with a new generation. Similar changes took place more slowly in the jejunum and ileum and very much more slowly in the large intestine. Feeding increased the rate of turnover.