THE FRONTIERS OF MEDICINE 



thirteenth to one-twentieth of the body weight. It is 

 far more than a fluid; it is a suspension containing many- 

 ingredients in the shape of formed and of dissolved ele- 

 ments which have an intimate bearing on life and health. 



MetchnikofF conceived the idea that the white blood 

 cells were the important element for attacking infectious 

 disease. He gave to them the name "phagocyte," with the 

 idea that they ate and digested cells. However, the white 

 blood cells represent but one of the types of formed ele- 

 ments in the blood. There are in addition, the red blood 

 cells and the platelets. The white blood cells number 

 about 5,000 to 7,000 for an amount of blood about the size 

 of a pinhead (1 cu. mm.). The red blood cells number 

 from 4,500,000 to 5,500,000 for the same quantity. The 

 blood platelets average from 150,000 to 250,000 for the 

 same amount. Unquestionably all of these constituents 

 have special functions, some of which have begun to be 

 understood; but about many of their functions there is 

 still a great deal of doubt. 



The red blood cells seem to be charged primarily with 

 the conveying of hemoglobin around the body. The hemo- 

 globin contains iron and is concerned with the distribution 

 of oxygen. If the hemoglobin is lessened in amount, there 

 is less oxygen carried, and the blood becomes exceedingly 

 pale. The normal amount of hemoglobin is listed at 100 

 per cent, but a person may have anywhere from 50 to 70 

 per cent and still feel fairly well. If the hemoglobin drops 

 much below this amount, one is likely to indicate the 

 deficiency by shortness of breath. The pallor associated 

 with lack of hemoglobin is typical. There are many condi- 

 tions in which the hemoglobin is altered or destroyed so 

 that it cannot carry oxygen. For instance, in poisoning 

 with carbon monoxid gas the hemoglobin is changed to a 

 form which cannot carry oxygen, and the person becomes 

 purple. 



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