PLATE XL. 



FIG. TOO. Transverse section of .an artery from a 

 vertical section of the skin of a guiueapig, coloured 

 with gold. a. Luiueti of the vessel, b. Endotheliuui 

 seen in profile, c. Iiitima. d. Circular muscles, 

 e. Adveutitia. /. Cellular elements of adveutitia. 

 p. 106. (Oc., 3 ; Obj., 7.) 



FIG. 99. Longitudinal section of a branch of the pulmo- 

 nary artery, from the lung of a guiueapig, the bronchi* of 

 which wei-e injected with dilute chromic acid. a. Intima. 



b. Circular layer of unstriped muscular fibres, cut across* 



c. Adventitia. p. 106. (Oc., 3; Obj., 7.) 



FIG. 102. A capillary 

 blood-vessel, the ca- 

 vity of which is extend- 

 ing into a branched 

 cell. (Oc.,3 Obj., 7.) 



Fig. ioi. Preparation from the normal omentum of a rabbit, firtst pencilled and then treated with silver, showing 

 the development of young capill -.ries. a. Capillary blood-vessels. 6. Capillaries only just hollowed out ; this pro- 

 cess of excavation is taking place in the branched connective tissue cells, d, which are ill relation with the capillary 

 wall. c. Vacuoles in the branched cells, e. Branched cells of the ground-substance. /. Migratory cells (Oc 3 

 Obj.. 7.) 



