ON THE STOMACH IN MAN AND THE ANTHROPOID APE. 25 



canal assumes in these cases is no doubt the product of the strong pull which these 

 fibres exert on the duodenal extremity of the pyloric canal. 



Pyloric Vestibule (PI. II. figs. 15 and 16). 



This subdivision of the pyloric part of the stomach intervenes between the incisura 

 angularis and the pyloric canal. It is usually pouched out on the side of the greater 

 curvature so as to form the ' coude de l'estomac,' of Cruveilhier or the camera princeps 

 of His. Erik Muller (40) has shown that the pyloric vestibule is much larger in the 

 child than in the foetus. It is interesting to note that in the chimpanzee the pyloric 

 vestibule is of small size, and in this respect resembles the stomach of the human foetus. 



Influence of Peristaltic Movements upon the Shape of the Stomach. 



Under this heading it is my desire to bring the anatomy of the stomach more fully 

 into line with the important results which have been recently obtained by investigation 

 into the movements of the organ during the progress of digestion. In some measure 

 it has been rendered possible to do this by the improved methods, now at our disposal, 

 of fixing in a permanent way certain phases of stomach activity which, through their 

 fleeting character and through rapid post-mortem change, have hitherto to a large 

 extent escaped attention. In the numerous discussions which have taken place upon 

 bilocular or hour-glass stomach, frequent reference is made to functional contraction 

 of the gastric wall, and many valuable observations on this matter have been recorded ; 

 but with this exception the anatomist has not given serious attention to the marked 

 changes which occur in the form of the organ as the result of the peristaltic move- 

 ments of its wall. These have been considered to lie more within the province of the 

 physiologist, and consequently, whilst the anatomy of the passive organ has been 

 studied with elaborate care, the anatomy of the active stomach has received little 

 thought. This is a very limited and circumscribed view to take of a subject so 

 important and so full of interest. The periods of digestive activity, as we know from 

 the labours of the physiologist,* are often very prolonged (see on this point the 

 observations of Hirsch (20)), and the stomach-forms presented at such times are as 

 characteristic and distinctive as those which are exhibited by the organ when in a 

 state of rest. 



The stomach represented in PI. III. fig. 23, obtained from an adult male, may be 

 taken as the type of a form which is not infrequently seen in cases where the subject 

 has been carefully preserved shortly after death. The organ is divided into two well- 

 defined portions by a deep constriction or infolding of the wall which cuts into the 



* "In a cat that finished eating 15 grammes of bread at 10.52 a.m., the waves (i.e. peristaltic waves 

 of the stomach) were running regularly at 11.00 o'clock. The stomach was not free from food till 6.12 p.m." 

 (Cannon (6).) 



TRANS. ROY. SOC. EDIN., VOL. XLV. PART I. (NO. 2). 4 



