THE MAST CELLS 



incompletely filled mast cells are seen in the delicate connective-tissue framework 

 of the omentum. 



Four days later (day eight) the omentum is virtually back to normal and 

 there is further recovery in the mesentery, though in some areas the mesenteric 

 windows are still devoid of mast cells or contain only occasional cells poor in 



20 r 



HIST. 

 IO 



ol 



• • OMENTUM 



O O MESENTERY 



DAYS 

 Fig. 33 



Experiment as illustrated in Fig. 32. Histamine content of omentum (• •) 



and mesentery (O O) shown in the tracings. (Riley and West (1955), 



J. Path. Bact. 69, 269.) 



granules. The pleomorphic fibroblasts scattered over the windows are still 

 present. 



By day fifteen recovery in all areas is complete and the histological picture 

 is normal. 



Histamine. The changes in the histamine content of the four regions 

 studied histologically are perhaps best seen in Figures 32 and 33, which show 

 both the absolute and the percentage changes in tissue histamine over the period 

 of the experiment. Briefly, the initial high values for the ears and subcutaneous 

 connective tissue fall in twenty-four hours to approximately 30 and 20 per cent of 

 normal, whereas in the case of mesentery and omentum, with lower starting 

 values, the histamine at the end of twenty-four hours has all but vanished. 



98 



