DISPERSAL OF THE VACUOLES 111 



more of the cell-granules show the remarkable danc- 

 ing Brownian movements, and the liquefying cyto- 

 plasm gradually involves the diffusion-vacuoles, one 

 by one. When the liquefying cytoplasm, which 

 immediately surrounds a vacuole, becomes of the 

 same consistency as the liquid within the vacuole, 

 the latter, which in reality is like a bubble of liquid 

 suspended in a liquefying jelly, suddenly bursts and 

 disperses, leaving a cup-shaped cavity in that portion 

 of the more central cytoplasm which has not yet 

 become liquefied. One by one all the vacuoles 

 disperse, and either immediately before or after 

 their dispersal general achromasia of the cell ensues, 

 for achromasia also depends on the liquefaction of 

 the cytoplasm. Vacuoles have never been seen to 

 "disperse" in a living cell; it is necessary for the 

 cytoplasm to liquefy for this to happen, and lique- 

 faction occurs only at death. Diffusion-vacuoles will 

 frequently be seen when experimenting with this 

 in-vitro method, large numbers of them sometimes 

 making their appearance in a single cell; but they 

 will all disappear after a short time. I have seen 

 them in all varieties of blood-cells (figs. 19, 20). 



The colour of the diffusion-vacuole depends on the 

 colour of the solution or jelly in \vhich the cell is 

 resting. If the jelly contains a red dye, such as 

 polychrome blue, the vacuoles will be red; ordinary 

 methylene blue causes them to appear blue. If no 

 stain is present the vacuoles will be colorless; if 

 stain is present the coloration of a vacuole is always 

 deeper than the colour of the surrounding jelly. We 



