

GASTRIC FLUID. 



26T 



this also serves to convey vessels from the submucous tissue, which 

 ramify among the follicles, and supply the materials for their secretion. 



Fig. 80. 



Fig. 81. 



Glandular from the coats of the Stomach, 

 magnified 45 diam. ; 1, fcom the middle of the 

 stomach; 2, from the neighbourhood of the 

 pylorus. 



Portion of the Mu- 

 cous membrane of the 

 Stomach, showing the 

 entrance to its secreting 

 tubes, in pits upon its 

 surface. 



The number of tubuli in each group is by no means constant. The fol- 

 licles do not, in general, open directly upon the surface ; but into the 

 bottom of small depressions or pits, which may be seen to cover the 

 membrane (Fig. 81). These pits are more or less circular in form ; and 

 are separated from one another by membranous partitions, which vary 

 in depth, and sometimes by pointed processes, which are capable of 

 erecting themselves in the manner just described. The diameter of 

 these pits varies from about l-100th to l-250th of an inch ; it is always 

 greatest near the pylorus. The number of the gastric follicles opening 

 into each, is usually from three to five ; but there are sometimes more. 

 470. The chemical composition of the Gastric fluid has been a subject 

 of much discussion, and can scarcely yet be regarded as precisely deter- 

 mined ; possibly it may vary in its nature, according to the state of the 

 system, and the kind of animal from which it is obtained. In all cases, 

 however, this fluid appears to contain a free acid, together with a pecu- 

 liar organic compound, Pepsine, which seems like albumen in a state of 

 change. It is in regard to the nature of the free acid that Chemists 

 are most at issue. Muriatic, phosphoric, acetic, lactic, and butyric acids 

 have each been detected in the gastric fluid ; but there are great diffi- 

 culties in the way of determining which of these acids are free, and 

 which are in combination. Thus, although it is very easy to obtain free 

 muriatic acid by distillation of the gastric fluid, yet this is by no means 

 an adequate proof of the previous presence of the acid in a free state ; 

 for it has been found that free lactic acid will decompose chloride of 

 sodium at an elevated temperature, forming (with water) lactate of soda 

 and muriatic acid ; so that the lactic may be the free acid of the gastric 

 fluid, the muriatic having been formed during the distillation, at the 

 expense of the chloride of sodium, which is a constituent of the gastric 

 fluid. It has been further determined, that muriatic and lactic acids 

 both possess a remarkable solvent power for albuminous matters, when 

 assisted by pepsine ; so that it is probable that they may replace one 

 another. The properties of the organic compound, named Pepsine, 

 which is peculiar to the gastric fluid, have been principally studied in 



