THE DYING CELL IN VIVO 529 



show that at low temperature they could not be found. His experi- 

 ments have been extended by Gajdos and Tiprez (977), who found 

 significant quantities of "verdoglobin" in addition to Heinz bodies 

 in citrated human blood stored at 37°C. for 3 days. 



So far only a very faint absorption band at about 660 mn has been noticed 

 after reduction of normal blood with dithionite (1707,1716), although Kiese 

 (1524) concluded from spectrophotometric studies that normal human blood 

 contains 0.4% "verdoglobin." Since this method depends ultimately on the 

 absorption curve of a sample of hemoglobin which completely lacks chole- 

 globin, it is worth referring to the difficulty which Lemberg and Legge 

 experienced in preparing such a sample (1706). Although there is little 

 doubt that traces of choleglobin are present, the changes observed in stored 

 blood merit quantitative reinvestigation. 



Small amounts of biliverdin, up to 0.7 mg. per 100 ml. of cells, 

 have been isolated from the normal washed erythrocytes of man, 

 sheep, horse, and rabbit (170^,1712; cf. also Chapter X, Section 5.). 

 It is of interest to compare this value with the normal level of sidero- 

 cytes in human blood, 0.5%. It can be accounted for on the basis of 

 10% of the hemoglobin in siderocytes being transformed into bili- 

 verdin. So far, no measurements have been reported on the biliverdin 

 concentration in stored blood. 



Increase in bilirubin in citrated or hirudinized blood which was 

 allowed to stand was first observed by von Czike (520) in 1929. 

 Ernst and Hallay (1700) tried to explain it by a change in cell volume, 

 but von Czike's results have been largely confirmed by a number of 

 workers (151,154,161,166,167,416,681). Both Barkan and Walker, 

 and Case measured the plasma iron at the same time. The latter 

 was found to increase much more than the bilirubin; six equivalents 

 of iron per equivalent of bilirubin was found in one case, and about 

 eleven in the other. In Barkan's experiments, carried out at 37°C., 

 the increase in bilirubin was equal to about 6% of the daily human 

 bilirubin production. Taken in conjunction with the biliverdin con- 

 tent of the erythrocytes, the increase in bilirubin indicates that some 

 intracorpuscular reduction of biliverdin takes place (cf. Section 8.2.). 



5.6. The Dying Cell in Vivo 



No reason is apparent why the changes observed in stored blood 

 should not also take place normally in vivo. The fact that freshly 

 transfused blood has as long a life in a compatible recipient as his 



