CHAPTER VII 



THE BLOOD AND ITS CIRCULATION 



J 204. Physical Properties of Blood. The blood is a red, 

 warm, heavy, alkaline fluid, slightly salt in taste, and has 

 a somewhat fetid odor. Its color varies from bright red in 

 the arteries and when exposed to the air, to various tints, 

 from dark purple to red, in the veins. 



The temperature of the blood varies slightly in different 

 parts of the circulation. Its average temperature near the 

 A surface is in health about the 



same, viz., 98 1 Fahr. The total 

 * H amount of the blood in the body 

 is about one-thirteenth of its 



total weight. 



* 205. Blood Corpuscles. If we 



put a drop of fresh blood upon a 



FIG 65. Red Blood Corpuscles kss slide and kce k a 



of Vanous Animals. (Magni- c . 



fied to the same scale.) cover of thin glass, we can flatten 



A, from proteus, a kind of newt; it OUt Until the Color almost dis- 



B, salamander; c, frog; D, frog app ears. If we examine this thin 



after addition of acetic acid, show- *- 



ing the central nucleus ; , bird; film With a miCrOSCOpe, WC SCC 



F, camel; G, fish; H, crab or that the blood is not altogether 



other invertebrate animal. _ . . ,,, r , - . .. ., 



fluid. We find that the liquid 



part, or plasma, is of a light straw color, and has floating 

 in it a multitude of very minute bodies, called corpuscles. 



There are two kinds of corpuscles, red and white. 

 "* 206. The Red Corpuscles. The red corpuscles are circular 

 disks about 7 ^W of an inch in diameter, and doubly 



136 



