288 H. E. JORDAN 
work was under way designed to test the hypothesis that the 
giant-cells of normal red bone-marrow represent potential mul- 
tiple hemoblasts like those of the yolk-sac, by a study of the 
marrow and the spleen during the regenerative stages following 
experimental hemorrhage. This work has now progressed to a 
point where a report of results seems warranted. ‘The results do 
not disprove the essential accuracy of this hypothesis, but neither 
do they give to it any support. The sections of this posthemor- 
rhagic marrow were subsequently employed, together with the 
control material, for a study of the significance of the alleged 
mitotic figures in the giant-cells. 
DESCRIPTION 
Two rabbits were used in this study. They were deprived of 
an amount of blood, drawn from the femoral vein, equal to 2 
per cent of their weight.1. Five days later they were killed, and 
specimens of spleen and of marrow from the femur were fixed 
severally in a mixture of 10 parts of formalin to 100 parts of a 
saturated normal-salt solution of corrosive sublimate and in 
Helly’s fluid. The stained sections of marrow showed extensive 
hemopoietic activity, but the giant-cells were not appreciably 
different from, nor more numerous than, those of normal con- 
trols, the marrow from which was similarly fixed and stained. 
The spleen also showed no increase in the number nor any 
change in the character of the very few relatively small giant- 
cells. 
More favorable results were to be expected from the marrow 
of the guinea-pig, for here larger numbers of the giant-cells are 
of the multinucleated type. It was assumed that these more 
extensively lobulated and multinucleated giant-cells were at 
least one step nearer the stage where under appropriate hemo- 
genic stimuli intracellular erythrocytes could differentiate, and 
that in consequence the relatively intensified posthemorrhagic 
hemopoiesis would involve these potential multiple hemoblasts. 
1 In these experiments I received valuable aid from Prof. J. H. Neff and Dr. 
D.C. Smith, of the University of Virginia Hospital staff. 
