THE BLOOD OF ANIMALS 305 



vores than in carnivores. The blood of birds, which is 

 the hottest known, being 104 F. which is 2-i4 F. 

 higher than mammals', is richest in red corpuscles. In 

 man, they constitute about one half the mass of blood. 

 The white globules are far less numerous than the red ; 

 they are relatively more abundant in venous than arte- 



FIG. 263. Capillary Circulation in the Web of a Frog's Foot, X 100: a, b, small veins; 

 d, capillaries in which the oval corpuscles are seen to follow one another in single 

 series; c, pigment cells in the skin. 



rial blood, in the sickly and ill-fed than in the healthy 

 and vigorous, in the lower vertebrates than in birds 

 and mammals. Their number is subject to great vari- 

 ations, increasing rapidly after a meal, and falling as 

 rapidly. 



There is less blood in cold-blooded than in warm- 

 blooded animals ; and the larger the animal, the greater 

 is the proportion of blood to the body. Man has about 

 DODGE'S GEN. ZOOL. 20 



