Fig. 19 



Fresh peritoneal spread from a rat killed by the rapid injection of stilbamidine. The bright 

 spots fluorescing in ultra-violet light are seen, in fig. 20, to be mast cells in which the 

 fluorescent stilbamidine has concentrated. This substance is also present in the lumen of 

 the upper vessel ( 70). (Riley (1953), J. Path. Baa. 65, 471.) 



* * 



Fig. 20 



The same spread as fig. 19, now counterstained with methylene blue and photographed 



in visible light minus the red filter. The dark mast cells correspond exactly with the 



fluorescent spots of the previous figure (x70). (Riley (1953), J. Path. Bad. 65, 471.) 



