296 



Comparative Animal Physiology 



TABLE 50 (continued). 



SIZE OF RED BLOOD CORPUSCLES IN MICRA DIAMETER, COUNT IN 



MILLION CELLS PER CUBIC MILLIMETER, AND HEMOGLOBIN 



CONTENT IN GRAMS PER 100 CUBIC CENTIMETERS 



OF BLOOD 



(Except where otherwise indicated) 



Data on size and red counts/"*' '"; hemoglobin data°^' ^^' ^^' ^' *'■ "'; when several values 



or ranges ot values were given, these have been averaged. Individual variability within 



a species is great, and the values given in this table are reasonable means. 



the pigments differ, however, in the nitrogenous base. Since heme is so wide- 

 spread in occurrence, it is not remarkable that it has been utilized in blood 

 pigments in a wide variety of unrelated animals. 



In hemoglobin the iron is found to be in the reduced (ferrous) state. The 

 iron content of human hemoglobin is 0.336 per cent (that of horse hemoglobin 

 is 0.38 per cent'"'"), and the heme content is 4 per cent. Each unit of hemo- 

 globin containing one atom of iron has a molecular weight of 16,400. Hemo- 

 globin in mammalian blood, however, consists of four units, and hence has 



*Grams per 100 cc. cells. 

 tHematocrit index. 



