BODY TISSUES AND FLUIDS 431 



their figures for normal adults are in substantial agreement with those re- 

 corded above. The few pathological data are of interest. In the cases 

 of pernicious anemia it will be noted that the hemoglobin dropped to the 

 low figure of about 3.5 per cent, while in the case of polycythemia it reached 

 23.^ per cent. 



Since the serum proteins, albumin and globulin, vary only, to a limited 

 extent, as previously noted, it is apparent that hemoglobin is ordinarily 

 not only the largest but also the most variable factor in the make-up of 

 the total solids. For this reason hemoglobin estimations provide a simple 

 method of securing information regarding the total solid content of the 

 blood. Underbill used the estimation for this purpose to excellent ad- 

 vantage in the treatment of poisoning with lethal war gases. It may be 

 assumed that daily fluctuations in the amount of hemoglobin in the cir- 

 culating blood are slight and that such fluctuations in the hemoglobin con- 

 tent are due to changes in blood volume. The frequent estimation of the 

 hemoglobin content of the blood in short series of experiments therefore 

 constitutes a simple means of following small changes in blood volume. 



There would seem to be no good reason why the clinical estimation of 

 hemoglobin should not be put on a more exact basis, comparable with many 

 of our other chemical blood analyses. Palmer (b) has recently described a 

 very simple and accurate method of estimating hemoglobin as carboxy- 

 hemoglobin, while Van Slyke's (c) method of determining the oxygen ca- 

 pacity of the blood is valuable in furnishing an occasional check on the col- 

 or imetrie methods and in the preparation of a blood standard. It should 

 also be noted that several recent papers have shown that hemoglobin, can 

 be accurately estimated by the acid hematin method of Sahli, provided 

 certain precautions are followed and a good colorimeter employed. 



Blood Cells. The blood cells (erythrocytes, leucocytes and blood 

 plates) are of interest in this connection only in so far as variations in 

 their content affect the chemical composition of the blood as a whole. The 

 figures which are generally given for the erythrocytes of the adult male 

 and female are 5 million per cubic millimeter for the former and 4.5 mil- 

 lion for the latter. Values higher than these are not uncommon but the 

 number rarely exceeds six million in perfectly normal individuals. Since 

 the red cells are composed of hemoglobin roughly to the extent of 90 per 

 cent it is apparent that the hemoglobin content, and the total solid content 

 as well, stand in fairly close relationship to the number of red cells. In 

 pernicious anemia the number of cells may be reduced to as small a num- 

 ber as 0.5 million or even less, while in some cases of secondary anemia 

 very low figures are found. Meyer and Butterfield have pointed out 

 that the high color index observed in many cases of pernicious anemia is 

 due to an increase in the oxyhemoglobin content of the red cells (see table 

 on p. 430). In the secondary anemias the color index is frequently low- 

 ered, apparently for the reverse reason. As would seem evident from the 



