STOMACH TUBES. 395 



surface : in the cat, and many other animals, the interfollicular 

 spaces, instead of being occupied by a plexus of vessels, con- 

 tain only a single vessel, which freely inosculates with the 

 neighbouring vessels, thus mapping out the spaces between 

 the follicles into somewhat irregular hexagons. (See Plate 

 LI. fig. 2.) 



STOMACH TUBES. 



The tubes of the stomach are prolongations of the base- 

 ment mucous membrane lining the follicles of that organ. 

 (See Plate L. figs. 3, 4, 5.) 



These tubes take a parallel course, end in irregularly dilated 

 extremities, are arranged in sets of three, four, or five tubes, 

 each of which corresponds with a follicle, and represents the 

 number of tubes which open into that follicle : it is only, 

 however, near their entrance into the follicles that they are 

 thus parcelled out : at their termination they would appear 

 to be independent of each other, and to be separated by 

 equal intervals, as represented in Plate L. fig. 3. 



The stomach tubes, unlike the mucous follicles, are filled 

 with spheroidal or glandular epithelial cells : these cells, 

 however, do not quite fill up the cavity of the tubes, but 

 leave in the centre of each a channel or canal, along which 

 the fluid secreted by the cells flows, until, at last, it reaches 

 the follicle into w r hich it is poured. 



The fluid secreted by these cells is, doubtless, the true 

 solvent or gastric fluid. 



The tubes I find to exist not merely in the stomach, to 

 which they are generally described as exclusively belonging, 

 but also in the upper part of the duodenum, which shows 

 that in the human subject, this portion of the intestine is 

 to be regarded as a kind of second stomach. I have ob- 

 served the occurrence of these tubes more than once both in 

 the duodenum of man, as well as of other mammalia. 



The fact of the mucous membrane lining the duodenum 

 being frequently dissolved some hours after death in the same 



i I 



