COMPOUND 48/80 ON RAT 



connective tissue and ears. In contrast, the extent of recovery in the peritoneal 

 cavity is limited. Well-stained mast cells are to be found in the adventitia of 

 the main vessels framing the mesenteric windows, but in the windows themselves 

 the cells are scanty and contain only a few pale and usually orthochromatic 

 granules. Here the histological picture is dominated by the general activation 



SOr 



40 



HIST. 



30 



( nfo 



20 



IO 



• • EARS 



O O SUBCUTI S 



100 



NORMAL 

 HIST. 



O 5 IO 15 20 25 30 35 



DAYS 



Fig. 32 



" Acute dosage ' experiment. Effect of two intraperitoneal injections of 48/80 



on the histamine content of the subcutaneous connective tissue (O O) and 



ears(# •) of rats. Histamine content expressed in ;xg./g. tissue in the upper 



tracings and in percentage of normal values in the lower tracings. Note the 

 rapid recovery of tissue histamine. (Riley and West (1955), /. Path. Bact. 



69, 269.) 



and increased basophilia of the loose mesenchyme, the entire network of small 

 blood vessels now standing out clearly in virtue of increased staining of the 

 cells forming their adventitial sheaths. Numerous well-stained pleomorphic 

 connective-tissue cells are also seen, scattered over the peritoneal windows and 

 giving a general appearance curiously like that of a tissue culture. At this 

 stage (day four) recovery is somewhat more advanced in the omentum, where 

 the milk spots contain many normal and some small and pale mast cells. Many 



G 97 



