METABOLISM AND TRANSPORT IN ANIMALS 



533 



Anemia 



One of the commonest abnormalities of 

 the blood is anemia. In this condition the 

 number of red corpuscles may be reduced 

 from the normal of about 5 million per cubic 

 millimeter to 1 million or less. The er\'thro- 

 cytes may also be deficient in hemoglobin. 

 The quantity of oxygen that can be carried 

 to the tissues is correspondingly reduced. 

 Of the several types of anemia, that known 

 as pernicious anemia is of greatest interest. 

 Before 1927 it was fatal in from 2 to 5 years 

 after onset, but at that time, due to the in- 

 vestigations of Whipple on dogs, and Minot 

 and Murphy on human beings, it was dis- 

 covered that liver was an effective method of 

 treatment. This is because there is an anti- 



anemic substance in the liver which stimu- 

 lates the regeneration of red blood corpus 

 cles. 



Harvey and the 

 circulation of the blood 



No discussion of circulation would be 

 complete without mention of the English 

 physician William Harvey (Fig. 457). By 

 means of experimental methods, he was able 

 to demonstrate that the blood circulates 

 through the body, being forced out of the 

 heart and returning again to the heart 

 (Fig. 387). This work threw an entirely new 

 light on the subject of physiology in gen- 

 eral, and had tremendous influence on the 

 progress of this science. 



Superior vena cava 

 Pulmonary artery 



Right ofrium 



Inferior vena cava 

 Right ventricle 



Capillaries of liver 

 Hepatic portal vein 



Renal vein 



■:\0;\ Nonoxygenoted 

 blood 



Capillaries of head 

 Artery to head 



Lung capillaries 



Pulmonary vein 



Left atrium 



Left ventricle 

 Dorsal aorta 



Hepatic artery 



Artery to intestine 



Capillaries of intestine 



Renal artery 

 Capillaries of kidney 



Capillaries of lower body 



Figure 387. Diagram showing the general scheme of blood circulation in the human body. 



