562 THE INTESTINAL CANAL, BY E. KLEIN AND E. VERSON. 



the pancreas not in all instances sharply defined towards the 

 longitudinal layer of muscles. This last frequently presents 

 areas where acinous groups of the pancreatic follicles penetrate 

 through foramina in it as far as the circular muscular layer, 

 whilst at other points a few muscular fibres are given off from 

 the longitudinal muscular tunic, which penetrate between the 

 acini into the substance of the head of the pancreas. Even the 

 circular layer may thus extend beyond its ordinary limits, and 

 in longitudinal sections made close to the pylorus in the rat 

 I have found a considerable fasciculus of smooth muscular 

 fibres given off from it, which, like the fasciculi already de- 

 scribed as entering the head of the pancreas, enter a group of 

 Brunner's glands, and here similarly subdivide amongst the 

 acini. 



In its further course the muscular tube presents nothing 

 remarkable, apart from its gradual attenuation, until it reaches 

 the valvula coli. Throughout this, as is particularly observable 

 in the new-born child, only the circular layer passes, whilst the 

 longitudinal layer is interrupted ; and indeed the bands of the 

 latter, proceeding on the one hand from the ileum, and on the 

 other from the colon, become considerably attenuated towards 

 the free border of the valve, whilst many muscular fasciculi 

 interlace with each other, and, finally, as my preparations show, 

 arch towards the adjoining circular fibrous layer. 



More or less considerable deviations from these arrrange- 

 ments occur in different animals. Thus I may mention, that 

 in the cat the longitudinal fibrous layer does not enter into 

 the formation of the valve, but usually, like the peritoneum, 

 extends uninterruptedly over it. On the other hand, the cir- 

 cular fibrous layer of the small intestine bears the relation to 

 that of the large intestine, of a thinner tube (ileum), which is 

 so introduced through a lateral aperture in the wall of a 

 thicker tube (colon), that it projects with a free border into the 

 lumen of the latter. In the dog, the circular fibrous layer of 

 the small intestine projects in this manner with its free bor- 

 der, but this difference is observable, that the longitudinal fibres 

 appear to be interrupted at the valve. 



If a portion of the muscular tube, which can easily be de- 

 tached with the forceps, be placed in a mixture of one part of 



