2U4 Till INIIRNAI. INVIKONMI N I Ol llll HOOY Part III 



he counted and their proportionate numbers determined. This is a routine 

 examination in many doctors' oflices and hospitals. 



Ikkugularitii-s in Numbers of Red Cells. Polycythemia, an increased 

 number of red cells, accompanies conditions in which the body fluids are de- 

 creased. Rarely there may be an overproduction of red cells in the red mar- 

 row. 



Anemia. In anemia the amount of hemoglobin is below normal; either 

 there is too little in the red cells or there are too few of them. There are many 

 causes and types of anemias. 



Anemias are caused by malnutrition, excessive blood loss, or destruction 

 of cells due to: ( 1 ) lack of iron in the diet resulting in sparsity of hemoglobin 

 in red cells; (2) hemorrhages from wounds, ulcers, etc; (3) defects in the 

 cells or poisons (hemolytic anemias); (4) an inherited condition, the Rh 

 factor (Chap. 20). 



Anemias are caused by defective formation of cells because of failure of 

 red cells to develop to maturity as in pernicious anemia; or damage to red 

 bone marrow due to certain chemical poisons, e.g., radium salts. 



The effects of various articles of diet, especially liver, on the regeneration 

 of hemoglobin was first noted by Dr. G. H. Whipple at the University of 

 Rochester. In 1926 Dr. G. R. Minot and Dr. W. P. Murphy at Harvard 

 University suggested that liver might be of value in treating pernicious anemia. 

 Although this has not proved to be a cure, it has become a treatment which 

 has kept thousands of persons living efficiently as long as it is continued. 

 It is now known that the liver discharges into the blood a substance (vitamin 

 Bij) essential for the blood cell-making function of the bone marrow, and 

 that pernicious anemia is caused by lack of this antianemic substance (Table 

 11.1). It is originally produced by the reaction of a specific secretion of the 

 stomach upon some substance in meat. The secretion by the stomach being 

 the inside product, it is called the intrinsic factor in contrast to the substance 

 in meat, an outside or extrinsic factor. Together these result in the antianemic 

 material which is stored in the liver, whence it is taken up by the blood. It is 

 this that eventually reaches the red marrow of the bones and stimulates the 

 development of the red cells (Fig. 12.7). 



White Cells. White cells (leucocytes) look white only when several are 

 banked together, otherwise they are colorless. They never contain hemoglobin, 

 are always nucleated, are more resistant to change than red cells and exist 

 in smaller numbers, in human blood — one to about 600 reds. They are older 

 in animal history than the red cells. Colorless nucleated cells occur in the 

 body fluids of planarians, annelids (earthworms, clamworms), insects, and 

 other arthropods. In mammals, some of them originate in the red bone 

 marrow and others in the lymphatic tissues (Fig. 12.8). In circulating blood 

 their number varies with the physiological changes in the body during the 



