FIG. 136. Vertical section of injected small intestine of rat. a. Villus showing its epithelium and dense 

 system of capillary vessels, which is developed from a central artery d, aud terminates iu two peripheral 

 veins, e. b. Mucosa. c. Portion of muteularit externa. p. 124. (Oc., 2; Oil., 2.) 



FIG. 137. Vertical section of a vilhis of the small intestine of a cat, hardened in chromic acid. a. Streaked 

 basal border of epithelium, b. Cylindrical epithelium, c. Goblet cells, d. Central lymph vessel, e. Smooth 

 muscular fibres which lie nearest to the lymph vessels. /. Adenoid stroma of the villus in which lymph 

 corpuscles lie. p. 124. (Oc., 3; Obj., 8.) 



FIG. 138. Transverse section of filiform papilla of tongue of rabbit, a. Epithelial covering of papilla:. 

 6. Capillary loop of papillae, c. Vessels of the mucosa. d. Vessels of longitudinal muscles, p. 122. (Oc., 2; 

 Obj., 2.) 



FIG. 139. Transverse section of large bronchus of human fdetus, from a lung hardened in chromic acid. 

 a. Ciliated cylindrical epithelium in layers. 6. Mucosa. c. Bundles of unstriped muscular fibre, d. Sub- 

 mucous tissue, showing cross sections of gland tubes, e. Portion of cartilaginous ring. /. On the left, an 

 artery cut through ; on the right, below, a vein. g. Trunks of medullated nerve fibre cut through, h. Section 

 of ganglion, p. 120. (Oc., 3; Obj., 4. Tube not drawn out.) 



(For figures of retina referred to in the text, tee figs. 157 and 158.) 



