HYDROID STRUCTURE OF THE STOMACH. 



51 



Fig. 6. 



fibrous matrix surrounding and supporting the basement membrane ; d, 

 small blood-vessels. 



B, horizontal section of a set of stomach tubes 

 proceeding from a single cell. The letters refer 

 to corresponding parts. The epithelium is glan- 

 dular, the nuclei very delicate, and the cavity of 

 -the tubes very small, and in some cases not visi- 

 ble. (From the dog, by Todd and Bowman, after 

 twelve hours' fasting.) 



It thus appears that there are at least two dis- 

 tinct classes of stomach follicles, differ- Varieties of 

 ing from each other in anatomical con- stomach foi- 

 struction, and, as there is now reason to ] 

 believe, also in physiological function, those which 

 are near the pylorus yielding a secretion which, 

 taken by itself, exerts only a tardy action in pro- 

 ducing the solution of protein bodies, but those 

 from the middle and other portions of the organ 



Horizontal section of stomach fol- T i ,1 i , ,1 T, 



licles and tubes magnified 200 di- accomplishing that Solution promptly. It IS SUS- 



pected that the acid of the gastric juice is yielded 

 by one class of these structures, and the 

 pepsin by the other. 



A general idea of the structure of these 

 secreting follicles may perhaps be obtained 

 by likening each of them to a little glove, 

 the hand of which opens into the stomach, 

 and the fingers project upon the submucous 

 tissue beneath. From the sides and tip of 

 each finger, cells may be supposed to arise 

 continually, and, as they are crowded for- 

 ward, they undergo development, leaving 

 the hand in a perfect condition, and deli- 

 quescing as they pass into the stomach. 



Though we have spoken of these folli- 

 cles as excavations or cup-like depressions 

 in the mucous tissue, according to the de- 

 scription usually given of them Hydroidcon . 

 by anatomists, it is to be under- struction of 

 stood that this view of their con- t] 

 struction is philosophically incorrect, for 

 each, instead of being a mere excavation, is 

 truly a distinct organism, analogous in struc- 

 The hydra. ture and many of its functions to a polype. 



