The development of the intramural nerve plexus of the gastro-intestinal tract.

The chicken intestinal tract from the 6th day of breeding until the 20th day after hatching was examined histochemically for acetylcholinesterase activity. The enzyme was detected first in the perikarya and subsequently also in the ganglion-cells processes. The appearance of the acetylcholinesterase reaction deposit was observed first in the stomach and duodenum and later in the rectum. The histogenetic development of the intramural plexus in the small gut proceeds caudad, but in the colon in the opposite way, i.e., craniad. In the duodenum and colon the nervous development is complete in chicken embryos of 11-12 days and in the rest of the small intestine in embryos of 13-14 days of breeding. In the human embryo of 60 mm CRL the development of the intramural plexus is already completed.