94 ELEMENTARY BIOLOGY. [CHAP. 



/?. The slower stream along the edge (inert 

 layer), containing many granular-looking co- 

 lourless corpuscles. 



c. The flow in the capillaries ; much slower than in 

 the arteries ; the frequent distortion of the red 

 corpuscles in the capillaries under pressure; 

 the elasticity of the corpuscles, as indicated by 

 the readiness with which they recover their 

 shape when the cause of distortion is removed ; 

 the manner in which the white corpuscles creep 

 along, and their tendency to stick to the capil- 

 lary wall. 



J. The lymphatic system. The full study of this system 

 is beyond the scope of this work ; the undermentioned 

 may however be made out with comparative ease. 



a. The sub-cutaneous lymph-spaces ; cf. Sect. C. a.j. 



b. The cisterna magna; cf. Sect. C. i. g. y. 



c. The circum-assophageal lymph sinus ; a loose fold 

 of mesentery embracing the base of the gullet, 

 opalescent in appearance. It becomes exceed- 

 ingly conspicuous if inflated, by introducing the 

 point of a blow-pipe beneath the adjacent peri- 

 toneum. 



d. The lymph-hearts ; small thin-walled sacs, paired 

 and pulsatile ; to be sought for while still beat- 

 ing, immediately on the death of the Frog. 

 They are, on either side — 



a. The posterior lymph-heart ; to be seen on re- 

 moving the skin of the back, lying a short 

 distance in advance of the cloacal aperture 



