Chap. 12 CIRCULATION AND TRANSPORTATION BODY FLUIDS 205 



24-hour day and in different parts of the circulatory system. Some white cells 

 are phagocytic. Motion pictures show them consuming bacteria, overstuffing 

 themselves with anything alien or broken that they can manage; even the 

 human appetite cannot be- so overreaching. Many white cells destroy them- 

 selves by their consumption of bacteria and others wander through the walls 

 of the intestine and are swept out of the body. 



Main Types. In structure there are two main types of white cells: granu- 

 locytes, those with specific granules in the cytoplasm and nuclei with lobes; 



Fig. 12.7. Diagram of the general location of the substances responsible for the 

 development of the red blood cells in the red marrow of bone. The intrinsic factor 

 is a specific secretion of the stomach; the extrinsic factor is a substance in meat. 

 Together these pass to the liver via the blood, are stored there, and in combination 

 are gradually given off via the blood to the red marrow of the bones. (From 

 Best and Taylor: The Living Body, ed. 3. Copyrighted by Henry Holt and Co. 

 Reprinted with their permission.) 



and nongranulocytes, those without specific granules in the cytoplasm and 

 with unlobed nuclei (Table 12.2, Fig. 12.5). White cells are very sensitive 

 in their reactions to chemical conditions both in the blood and outside 

 the body when they are treated with stains. They are classified according to 

 their reactions to the latter. 



Granulocytes are of three types, whose names end in phil indicating their 

 love or affinity for the respective stains, eosinophils (the stain, eosin), baso- 

 phils (basic stains), and neutrophils (neutral stains). The group of non- 

 granulocytes contains the monocytes and the lymphocytes (Table 12.2 and 

 Fig. 12.5). 



Functions. The neutrophils, lymphocytes, and monocytes, together with 

 the phagocytic cells of the connective tissue constitute one of the body's most 

 important defenses against poisons and invading organisms. All leucocytes 



