PLATE I 



EXPLANATION OF FIGURES 

 VITAL DYES 



1 Spleen four days after injection of coarse carmine granules. The black 

 bodies are carmine. Insert shows an endothelial cell with a pseudopodial proc- 

 ess full of carmine. 



2. Liver five days after injection of trypan blue. Black bodies are trypan 

 blue except in the cell at x which contains both trypan blue and normal black 

 pigment. 



3 to 5 Gill five days after injection of trypan blue. Figure 3 shows arterial 

 arch and sinuses at the base of the filaments lined with endothelium which has 

 ingested trypan blue, and containing free phagocytes filled with the dye; figure 4 

 shows normal endothelium from a sinus, and figure 5 shows two sinuses from 

 figure 3, showing the reaction to the injected dye. The phagocyte at x contains 

 both blue and black granules. 



144 



