VILLI OF INTESTINES IN THE HOUSE. 67 



nucleated cells and free nuclei. Besides which there are large 

 cells, some of which are nucleated and others not, but both of 

 which contain blood-corpuscles in different conditions. The 

 Malpighian corpuscles of the spleen are white vesicular-look- 

 ing bodies, varying in diameter from l-35th to l-60th of an 

 inch, and consisting of two coats, the external continuous, as 

 it would seem, with the trabecular tissue supporting the 

 arteries. A soft white semi-fluid matter fills them ; this con- 

 tains microscopic globules resembling, with the exception of 

 colour, the corpuscles composing the red pulp of the spleen. 

 Both much resemble chyle-corpuscles. 



The lymphatics of the spleen are a superficial and a deep 

 set. The superficial set run under the serous coat towards the 

 hilum. The deep lymphatics accompany the blood-vessels, and 

 proceed from the hilum along the gastro-splenic omentum to 

 the neighbouring lymphatic glands. 



Villi of the Intestines. The villi are confined exclusively 

 to the mucous membrane of the small intestine. They are 

 minute vascular processes less than a line in length, covering 

 the surface of the mucous membrane (in the human body) in 

 the proportion of about twenty-five to every square line, 

 whence they give to the mucous surface a peculiar velvety 

 fleecy appearance. When empty they are flat and pointed at 

 their summits ; when full of chyle they are cylindrical. At 

 the base of each villus one or more lacteal vessels enter, which 

 pass up the middle and reach near to the tip, to terminate in 

 a somewhat dilated extremity without any perforation or open 

 extremity. Two or more small arteries are spread within each 

 villus, and from their capillaries proceed, through the base of 

 the villus, one or two minute veins. A thin layer of organic 

 muscular fibres forms a kind of hollow cone around the central 

 lacteal, and is therefore situated beneath the blood-vessels and 

 much of the granular basis of the villus. This muscular cone 



