THE VILLI. 



307 



Beneath the basement or limiting membrane there is a 

 rich supply of blood-vessels. Two or more minute arteries 

 are distributed within each villus ; and from their capil- 



Fig. Si.* 



laries, which form a dense network, proceed one or two 

 small veins, which pass out at the base of the villus. 



The layer of the muscularis mucosa in the villus forms a 

 kind of thin hollow cone immediately around the central 

 lacteal, and is, therefore, situate beneath the blood-vessels. 

 The addition of acetic acid to the villus brings out the 

 characteristic nuclei of the muscular fibres, and shows the 

 size and position of the layer most distinctly. Its use is 



* Fig. 81. (Slightly altered from Teichmann.) A. Villus of sheep. 

 B. Villi of man. 



x 2 



