SMALL VEINS. 



145 



it is very much less developed. In its place we find in 

 the middle coat of the larger veins toughish layers, which 

 are not characterized so much by the absence of muscu- 

 lar elements as by the greater abundance of elastic ele- 

 ments which run in a longitudinal direction and are 

 found in greater or less quantity in different localities. 



FIG. 4*7. 



In an inward direction there follow next the softer and 

 more delicate layers of connective tissue of the internal 



FIG. 48. 



Fig. 47. A, Epithelium from the femoral artery (' Archiv f. path. Anat.,' vol. iii.,. 

 figs. 9 and 12, p. 696). a. Division of nucleus. 



B. Epithelium from veins of considerable size, a, a. Largish, granular, round, 

 uni-nuclear cells (colourless blood-corpuscles ?) 5, b. Oblong and spindle- shaped 

 cells, with divided nuclei and nucleoli. c. Large, flat cells, with two nuclei, of 

 which each has three nucleoli, and is in process of division, d. Coherent epithe- 

 lium, with the nuclei in a state of progressive division, one cell having six nuclei. 

 320 diameters. 



Fig. 48. Epithelium from the vessels of the kidney. A. Flat, spindle-shaped 

 cells with longitudinal folds and large nuclei from a new-born child. B, Ribbon- 

 like, nearly homogeneous, plate of epithelium with longitudinal nuclei from an 

 adult. 350 diameters. 



10 



