BODY TISSUES AND FLUIDS 429 



In chronic nephritis with uremia the total proteins may be nearly normal 

 but the globulin is usually increased. Except in very severe diabetes the 

 findings are practically normal. In pernicious anemia the total proteins 

 are not as low as would be expected from examination of the whole 

 blood, being higher than in nephritis with edema. 



Fibrinogen. According to Whipple the normal fibrinogen limits for 

 the human subject may be given as 0.3 to 0.6 per cent with an average of 

 0.5 per cent per 100 c.c. of plasma. In pneumonia and septicemia fibrino- 

 gen is much above normal, reaching 0.9 per cent, while in acute liver in- 

 jury it drops to a very low level or even zero in some fatal cases. In chronic- 

 liver disease fibrinogen often falls markedly and may cause bleeding 

 (cirrhosis). In general cachexias, such as sarcomatosis, nephritis and 

 miliary tuberculosis, the fibrinogen may be quite low, 0.1 per cent. 



Hemoglobin. Hemoglobin is the iron containing and oxygen carry- 

 ing pigment of the red blood cells. It is a conjugated protein, composed of 

 the histon, globin, and hemochromogen, the iron containing pigment. In 

 the presence of oxygen the latter body is rapidly transformed into hematin. 

 Hemoglobin is crystallizable, and peculiar in its high iron content, which 

 amounts to 0.34 per cent. Under normal conditions it is quite completely 

 saturated (95 per cent) with oxygen in arterial blood, although in the 

 case of venous blood the oxygen is ordinarily reduced to about 75 per cent 

 of saturation. Owing to this fact the hemoglobin of the blood may be 

 more correctly referred to as oxyhemoglobin. Oxyhemoglobin has a bright 

 red color but (reduced) hemoglobin is darker and more violet or purplish, 

 hence the darker color of venous blood. For further properties of hemo- 

 globin and its many derivatives reference may be made to Hammarsten. 



The estimation of hemoglobin was apparently the first chemical de- 

 termination in the blood to find extensive clinical application. It seems un- 

 fortunate that most of the estimations recorded should have been made 

 employing an empirical scale with 100 as the normal, especially since 

 the 100 is somewhat of a variable factor with different methods owing 

 to different standardizations. The hemoglobin content of the blood 

 varies widely not only in disease, but also in different age periods as re- 

 cently pointed out by Williamson. For this reason it would appear more 

 logical to record the hemoglobin, as we do other blood determinations, in 

 grams per 100 c.c. or per cent. 



The table below compiled from observations of Williamson well illus- 

 trates the changes in the hemoglobin content of the blood over different 

 age periods. The figures were obtained with the accurate spectrophoto- 

 metric method, fifteen or more of both males and females being employed 

 for each age group. From this table it will be noted that during the first 

 few days of life the hemoglobin content exceeds 20 per cent,, but then 

 drops rather abruptly the third month to below 14 per cent and does not 

 pass this figure until the tenth year. During the adult period of life in 



