316 



MANUAL OF PHYSIOLOGY. 



where the auricles are dilated and distended with blood this may 

 cause a definite pulsation, which becomes visible in the great 

 veins of the neck. 



FIG. 142. 



Small portion of Frog's Web, very highly magnified. (Huxley.) A. Wall of capillary 

 vessels. B. Tissue lying between the capillaries, c. Epithelial cells of skin, only shown 

 in part of specimen where the surface is in focus. D. Nuclei of epithelial cells. E. 

 Pigment cells contracted, r. Red corpuscles (oval in the frog). G. H. Red corpuscles 

 squeezing their way through a narrow capillary, showing their elasticity, i. White 

 blood cells. 



