A STAINED NUCLEUS MEANS DEATH 51 



After a short time the extrusion of pseudopodia 

 ceases, and it will then be noted that general retraction 

 (figs. 8, 9) of pseudopodia begins to occur. In the 

 meantime the lobes of the nuclei of the polynuclear 

 cells begin to turn a faint blue colour (fig. 10). If 

 two or more leucocytes happen to be in the same 

 field, it will be seen that they all behave in a like 

 manner, for the stain affects them all equally. In a 

 few moments all the amoeboid movements cease, for 

 death is about to occur, and then, sometimes quite 

 suddenly, the nuclei turn bright scarlet (fig. 11) and 

 the death of the cell takes place. 



We have never yet seen a cell show any amoeboid 

 movements when its nucleus has stained scarlet. By 

 mixing some blood with a citrated solution of stain 

 one can cause first the granules and then the nuclei 

 of the leucocytes to stain, the difference depending 

 on the length of time the mixture has been made. 

 If now cells with only their granules stained are placed 

 on to a jelly-film which contains an alkaloid, we can 

 excite these cells, showing that they are alive. But 

 if their nuclei are stained scarlet, no excitation or move- 

 ments of any sort can be produced, and there can be 

 little doubt, therefore, that the staining of the nu- 

 cleus kills the cells. White blood-corpuscles do not 

 seem to mind the staining of their granules; but the 

 staining of their nuclei invariably causes their death. 

 This is a rule to which we have never yet seen an 

 exception in any cell which we have examined. A 

 stained nucleus is incompatible with life. 1 



1 We have tried several stains, but this rule holds good with them all. 



