The vital staining of mitochondria with janus green etc. 281 



1. That the diethylsafranin, which is also a specific dye for 

 mitochondria, penetrates the cell and colors it diffusely but does not 

 stain them. 



2. I have been able to stain mitochondria with janus green in 

 the nonnucleated red blood cells in the bone marrow of the guinea 

 pig'. There was no diffuse coloration of the cytoplasm with the dye. 

 Repeated attempts gave me only one example of what appeared to 

 be mitochondria stained with janus green in the nonnucleated red 

 blood cells of the circulating- blood of guinea pigs. This cell appeared 

 in a smear taken from the ear vein of a guinea pig about six months 

 old. It is apparent, therefore, that hemoglobin does not prevent the 

 mitochondria from staining because it seems to be just as abundant 

 in the nonnucleated red blood cells of the bone marrow as in those 

 of the circulating blood. In the one the mitochondria are stained, in 

 the other they are not. Furthermore, there is no reason to suppose 

 that the permeability of the cell membrane in the circulating blood 

 should be less than in the bone marrow and thus prevent the diffu- 

 sion of the stain into the cell. 



3. Moreover, these observations of mine with vital dyes are in 

 accord with those of Meves on fixed cells. He found ('11, p. 495) 

 that, in fixed and stained preparations of the bone marrow of a 

 guinea pig, the mitochondria decreased in number in the differentiating 

 red blood cells, that a few of them persisted for a short time after 

 the disappearance of the nuclei and that they are totally absent in 

 the nonnucleated red blood cells of the circulating blood. 



The conclusion is therefore warranted that mitochondria are 

 totally absent in the nonnucleated red blood cells of the circulating 

 blood of man. 



My observations on the occurrence of mitochondria in some 

 platelets and their absence in others may likewise be interpreted 

 in two ways. 



It may .be a question of the age of the platelet; since there is 

 considerable evidence that cells devoid of nuclei do not contain mito- 

 chondria (Guilliermond's studies on Bacteria, '11, p. 200), and that they 

 speedily disappear in cells the nuclei of which are degenerating (Meves' 



