ON THE STOMACH IN MAN AND THE ANTHROPOID APE. 15 



child's stomach (fig. 16) the lumen is obliterated by closely packed longitudinal folds 

 of mucous membrane. The communication between the canal and the vestibule is 

 placed close to the lesser curvature, whilst opposite to this the vestibular part of the 

 greater curvature forms an expanded bay or pocket. But Erik Muller has given such 

 an admirable account of the pyloric canal in the foetus and child that it is not necessary 

 to say more on this subject, beyond emphasising the fact that it is in these early 

 stages that the best conception of this part of the stomach as a distinct section of 

 the organ can be obtained. 



In the adult it is much more common to find the canal partially or completely 

 expanded, and in this condition its demarcation from the pyloric vestibule becomes less 

 pronounced. Its tubular character, however, is rarely entirely lost, and when a section 

 is made through the stomach in the plane of the curvatures, the appearance presented 

 by the interior makes the subdivision between these two parts of the stomach sufficiently 

 clear. Every phase, from the most complete contraction, with obliteration of the cavity, 

 to the fullest degree of expansion of the pyloric canal, is met with ; but in very few 

 cases, and these, as a rule, not normal specimens, do we see the pyloric canal so 

 expanded that its cavity merges into that of the pyloric vestibule without any indication 

 of subdivision in the interior of the organ. 



The problem as to what are the conditions which produce, on the one hand, a 

 firmly contracted, cylindrical canal, with an obliterated lumen, and, on the other 

 hand, a partially relaxed or completely patent and capacious pyloric canal, is one 

 of great difficulty. An identical contraction-phase of the canal is not infrequently 

 associated with absolutely different contraction-phases of the rest of the stomach. 

 Thus, in cases where the stomach is contracted and empty, it does not follow that 

 the pyloric canal is contracted likewise. Indeed, in such conditions of the stomach, 

 it has been my experience to find the canal as a rule partially expanded. 

 Again, in the widely expanded stomach all phases in the condition of the pyloric 

 canal are met with — from one tightly contracted in its whole length to one which is 

 partially relaxed or completely dilated. Still, I think it may be assumed that the 

 contracted canal is more frequently found associated with the full than with the 

 empty stomach. 



From the circumstances stated above, we may reasonably infer that the musculature 

 of the pyloric canal in all probability acts to some extent independently of that of 

 the rest of the stomach, and is under the control of a special nervous mechanism. 



The extremity of the pyloric canal protrudes into the commencement of the 

 duodenum (PI. II. figs. 15 and 16), so that, when viewed from the duodenal side, it 

 presents the appearance of a smooth, rounded knob with a small puckered aperture, the 

 pyloric opening, in its centre, and surrounded by a shallow groove or fornix. The 

 resemblance which it presents, as I pointed out many years ago, to the portio vaginalis 

 of the cervix uteri is very striking. In the full-time foetus the protrusion of the 

 termination of the pyloric canal into the duodenum is more marked than in the adult, 



