Pio. 25.— Very small Portion of Fig. 24 verv highly magnified. 



A, walls of capillaries ; B, tfssue of web lying between the capillaries ; 

 C, cells of ejjidermis covering web (these are only shown in the right- 

 hand and lower part of the field ; in the other part.s of the field the focus 

 of the microscope lies below the epidermis) ; D, nuclei of these epidermic 

 cells ; E. pigment cells contracted, not partially expanded as in Fig. 24 ; 

 F, red blood-corpuscle (oval in the frog) passing along capillary— nucleus 

 not visible : G. another corpuscle squeezing its way through a capillary, 

 the canal of which is smaller than its own transverse diameter; H, 

 another bending as it slides round a comer ; A', corpuscle in capillary 

 seen through the epidermis ; /, white blood-corpuscle. 



6 



