ANEMIA 67 



sides the loss of blood there is also a toxic effect either from the 

 parasites themselves or from substances produced in the digestive 

 tract. An anemia may occur in cases of disease complicated by- 

 single or several hemorrhages, as in malignant tumors and bleed- 

 ing ulcers. 



After exudation. The loss of blood from hemorrhagic exu- 

 dates may be considerable. With fibrinous and with hemorrhagic 

 exudation the loss of blood or albumins may determine a severe 

 anemia, as for example in chronic suppuration, exudative nephritis, 

 purpura hemorrhagica and malignant endocarditis. 



In diminished nutrition. Again anemia may be due to dimin- 

 ished nutrition and defective hygiene, as with improper food, 

 diseases of the masticatory apparatus, broken jaw, diseased teeth, 

 pharyngeal troubles interfering with swallowing, in severe febrile 

 conditions, and in unsanitary surroundings, as dark, damp, poorly 

 ventilated stables. Irregularity of feeding and irregular work 

 have been thought to be partially responsible for anemia. 



In diminished activity of the blood forming organs. Dimin- 

 ished activity of the blood forming organs occurs in many of the 

 infectious diseases by the action of toxic substances upon the blood 

 forming tissues and by a changed structural condition in them. 

 For example, in the leucocytosis of pneumonia (Ewing) there is a 

 proliferation in the bone marrow of myelocytes at the expense of 

 normoblasts. Intoxication by lead, mercury or arsenic produces 

 a lessened activity of the blood forming organs. 



In increased destruction of red corpuscles. An increased 

 destruction of erythrocytes occurs in septic processes, septicemia, 

 pneumonia, malignant endocarditis, tuberculosis, malignant 

 tumors (cancer), anthrax in the cow, azoturia in the horse, Texas 

 fever in cattle. The increased katabolism of albumins in febrile 

 conditions and also in afebrile cachexias may be a factor in pro- 

 ducing anemia. 



The changes in the blood in anemia vary a great deal. In many 

 cases there is simply a lessened amount of hemoglobin and a low- 

 ered specific gravity, the number of corpuscles remaining prac- 

 tically normal. Changes in the size, shape and staining reaction 

 of the corpuscles may be seen in less mild cases. Many of the 

 corpuscles may show lack of hemoglobin, indicated by the increased 

 size of the central clear area. A greater than normal variation in 



