THE GASTRIC FLUID. 219 



being probably engaged in separating the thin alkaline mucus, 

 which is always present in greater or less quantity, while the 

 larger glandular cells probably secrete the proper gastric juice. 



Near the pylorus there exist glands branched at their deep 

 extremities, which are lined throughout by cylinder-epithelium 

 (Fig. 70, a), and probably serve only for the secretion of 

 mucus. 



All the tubular glands, while they open by one end into the 

 cavity of the stomach, rest by their blind extremities on a bed 

 or matrix of areolar tissue (Fig. 69), which is prolonged up- 

 wards between them, so as to invest and support them. 



Lenticular Glands. Besides the cylindrical glands, there 

 are also small closed sacs beneath the surface of the mucous 

 membrane, resembling exactly the solitary glands of the intes- 

 tine, to be described hereafter. Their number is very variable, 

 and they are found chiefly along the lesser curvature of the 

 stomach, and in the pyloric region, but they may be present 

 in any part of the organ. According to Dr. Brinton they are 

 rarely absent in children. Their function probably resembles 

 that of the intestinal solitary glands, but nothing is certainly 

 known regarding it. 



The bloodvessels of the stomach, which first break up in the 

 submucous tissue, send branches upward between the closely 

 packed glandular tubes, anastomosing around them by means 

 of a fine capillary network with oblong meshes. Continuous 

 with this deeper plexus, or prolonged upwards from it, so to 

 speak, is a more superficial network of larger capillaries, which 

 branch densely around the orifices of the tubes, and form the 

 framework on which are moulded the small elevated ridges of 

 mucous membrane bounding the minute, polygonal pits before 

 referred to. From this superficial network the veins chiefly 

 take their origin. Thence passing down between the tubes, 

 with no very free connection with the deeper intertubular capil- 

 lary plexus, they open finally into the venous network in the 

 submucous tissue. 



The nerves of the stomach are derived from the pneumo- 

 gastric and sympathetic. 



Secretion and Properties of the Gastric Fluid. 



While the stomach contains no food, and is inactive, no 

 gastric fluid is secreted; and mucus, which is either neutral or 

 slightly alkaline, covers its surface. But immediately on the 

 introduction of food or other foreign substance into the stom- 

 ach, the mucous membrane, previously quite pale, becomes 

 slightly turgid and reddened with the influx of a larger quan- 



