I2 4 



NUTRITION OF FARM ANIMALS 



174. Red blood corpuscles. These are by far the more 

 numerous of the two kinds. In man they are round like "a coin 

 but thicker at the edges than in the center, and have a diameter 

 of 0.0060-0.0085 millimeter. Their number is enormous, being 

 estimated at 4 to 5^ millions per cubic millimeter of blood. 

 To them the color and opacity of the blood are due. 



The corpuscles of each species of animal are peculiar to it, both 



as to shape and size, but 

 their general characteristics 

 are the same in all. Those 

 of most animalsaresmaller 

 than those of man. Each 

 corpuscle is a cell, having 

 no nucleus but containing 

 as its characteristic ingre- 

 dient the conjugated pro- 

 tein haemoglobin to which 

 the red color of the blood 

 is due. Haemoglobin is a 

 crystalline substance and 

 it has recently been shown 

 by Reichert that the 

 haemoglobin of each spe- 

 cies of animal has its spe- 

 cific crystalline form and 

 properties. 



175. White blood corpuscles. The white corpuscles are 

 colorless, nucleated cells which are not confined to the 

 blood but which, by means of ameboid movements, are able 

 to pass through the walls of the blodd vessels and the 

 lymph spaces of connective tissue as the so-called " wander- 

 ing cells." They have important functions, especially in 

 protecting the body from disease, but need not be further 

 considered here. 



176. Blood platelets. In addition to the two kinds of cor- 

 puscles, the blood contains more minute nucleated cells, rang- 

 ing in diameter from 0.0003-0.0005 millimeter, called blood 

 platelets, or thrombocytes. They are much more abundant 

 than the white corpuscles and are thought to be concerned in 

 the coagulation of the blood. 



FIG. 16. Blood corpuscles. 



Above are shown nine red corpuscles, highly mag- 

 nified; below, less highly magnified, the appearance 

 of the blood soon after being drawn. (Hough and 

 Sedgwick, The Human Mechanism.) 



