128 



THE BLOOD 



The red corpuscles are not all alike. In almost every specimen of blood a 

 certain number of corpuscles smaller than the rest may be observed. They 

 are termed microcytes, or hematoblasts, and are probably immature corpuscles. 



A peculiar property of the red corpuscles, which is exaggerated in in- 

 flammatory blood, may be here again noticed, i. e,, their great tendency to 



FIG. in. Illustration exhibiting the typical characters of the red blood-cells in the 

 main Divisions of the Vertebrata. The fractions are those of an inch, and represent the 

 average diameter. In the case of the oval cells, only the long diameter is here given. It is 

 remarkable, that although the size of the red blood-cells varies so much in the different 

 classes of the vertebrate kingdom, that of the white corpuscles remains comparatively 

 uniform, and thus they are, in some animals, much greater, in others much less, than the 

 red corpuscles existing side by side with them. Modified from Gulliver. 



adhere together in rolls or columns (rouleaux), like piles of coins. These 

 rolls quickly fasten together by their ends, and cluster; so that, when the 

 blood is spread out thinly on a glass, they form a kind of irregular network, 

 with crowds of corpuscles at the several points corresponding with the knots 

 of the net, figure 109. Hence the clot formed in such a thin layer of blood 

 looks mottled with blotches of pink upon a white ground. 



