148 



THE CIRCULATION OF THE BLOOD 



thus completes the circuit. The shortest time that a 

 drop taking the shortest route can make the circuit is 

 estimated at fifteen seconds. Between one and two min- 

 utes is required for all the blood in the body to pass 

 once through the left ventricle. 



Lymphatics. The small portion of the blood com- 

 prising the plasma and the white blood corpuscles, which, 

 as we saw, escaped from the capillaries into the space 



White corpuscle 

 penetrating 

 wall of capillary 



&-~ White corpuscle 



in tissue 

 Red corpuscle 



From artery 



To vein 



Fio. 89. Migration of the white blood corpuscles from the capillaries of a frog 

 into the tissues during inflammation. (After Warren). 



between the muscle cells alone remains to be accounted 

 for. After leaving the capillaries, the plasma and white 

 blood corpuscles are known as lymph, 1 because of their 

 clearness and lack of color. The spaces between the cells 

 into which the lymph escapes are irregular in size and 

 shape and have no definite boundaries. They blend to- 

 gether to form communicating spaces of considerable 

 extent. The lymph in these intercellular spaces is con- 



1 Lymph may be seen characteristically under the skin in the 

 form of "water blisters." 



