572 



AMPHTBJA. 



When the blood clots, the plasma becomes a colourless 

 serum, traversed by coagulated fibrin filaments, the red 

 corpuscles often arrange themselves in rows, and the white 

 corpuscles are entangled in the coagulated shreds. When 

 the web of a living frog is examined under the microscope, 



C. 



U. 



FIG. 279. Arterial system of frog. 



/., Lingual ; c., carotid ; s., systemic ; cif., cutaneous ; /., pulmon- 

 ary ; ;'., occipito-vertebral ; l>r., brachial ; cm., coeliaco- 

 mesenteric ; r., renal; //., common iliacs ; //., haimorrhoidal. 



it will be seen that the flow of blood is most rapid in the 

 arteries, more sluggish in the veins, most sluggish in the 

 capillaries or fine branches which connect the arteries and 



