274 



THE BLOOD. 



presence of red corpuscles to the number of 8,000,000 per 

 cu.mm. It does not necessarily follow, however, that this is an 

 absolute increase, for it may be due to loss of the water of the blood, 

 caused by increased evaporation from the body, and to increased 



FIG. 146. Oliver's hemacytometer : a, measuring pipet: b, dropper to contain 

 Hayem's fluid; c, mixing tube graduated in percentages; d, mode of making the 

 observation (this must be done in a dark room) ; a, b, and c are natural size. 



arterial tension, by which the amount of lymph is increased. In 

 conditions of apparent health so small a number as 1,600,000 has 

 been found. In newborn children, 5,000,000 per cu.mm. have 

 been estimated. 



Color of the Red Corpuscles. A single corpuscle is of a 



