Abstract
The following results were obtained through the macro- and microscopic observation of the muscular layers of human and canine intestines, which were prepared with 20% of HNO3.
1. Both inner circular and outer longitudinal layers of the intestine are formed by the main fasciculus (named by the author) which consists of 3-7 fasciculi. The main fasciculus of the inner circular layer is spiral in shape.
2. In human, most of the main fasicucli of the inner circular layer run clock-wise spiral course, but in dogs, most of the main fasciculi of the inner circular layer run counter-clock-wise spiral course. Between the main fasciculi, there are many branches forming a fine net-work.
3. The main fasciculi of the longitudinal layer of the intestine are parallel running longitudinally. The main fasciculi are connected with many branches. No difference in human and dog is noted.
4. Dog's ileocecal valve is formed by fasciculi of the inner circular and outer longitudinal layers of the small intestine and the inner circular layer of the large intestine. The principal layer is the inner circular layer of the small intestine.
