FUNCTIONS OF THE INTESTINES. 315 



acute expression of suprarenal insufficiency, and that blood- 

 plasma is the normal excipient for chemical protective agencies, 

 suggest the following deduction: The glands of Lieberlcuhn and 

 the duodenal glands of Brunner supply a secretion having for its 

 object to asepticize, and prevent the putrefaction of, the intestinal 

 contents. 



A kindred, though far more important, process is the pro- 

 tection afforded the organism where poisons of all kinds are 

 most likely to penetrate the blood-stream: i.e., the organs of 

 the intestinal wall connected with absorption. 



Villi and Lymph- follicles. The villi, the solitary lymph- 

 follicles, and the agminated lymph-follicles, or Peyer's patches, 

 are considered together, because they appear to us to represent 

 parts of a single system. 



The structural similarity between the walls of the stomach 

 and those of the intestine must be set aside here, since the 

 function referred to, i.e., absorption, a predominating one 

 in connection with the intestines, can hardly be said to be 

 worth considering as a factor of gastric functions. Conversely, 

 the villi distributed throughout the whole small intestine are 

 especially adapted for this purpose. Besides the capillaries, 

 nerves, muscular tissue, basement membrane, and epithelium, 

 these structures contain a lymph-trunk, or lacteal, the purpose 

 of which is to take up nutritional agencies from the intestinal 

 contents as they pass along. 



Each villus may be considered as a sort of "reversed" 

 gland, if a sweat-gland is taken as standard. The epithelium 

 is outside, i.e., exposed in the intestinal canal, while under 

 the epithelium lies the basement membrane. Combined, these 

 two constitute a glove-finger-like projection inside of which 

 are the structures that we found over the basement membrane 

 in the sweat-gland. The capillaries form a close-meshed net- 

 work not only in contact with the inside of the basement 

 membrane, but entwined with considerable connective tissue 

 strewn with leucocytes, the tissue and cells constituting "lym- 

 phoid tissue." We said "connective tissue," but at this point 

 we must emphasize the fact that it is not true connective tissue, 

 as met with elsewhere, but a fenestrated membrane made up 

 entirely of star-like cells that give off thin projections, or 



