THE MAST CELLS 



This experiment led naturally to a consideration of the effects of bases in 

 general on mast cells, from which the general conclusion was drawn that any 

 change in the pH of the surrounding medium from neutrality towards the 

 alkaline side favours the swelling and disruption of the tissue mast cells. 

 Ammonia, the simplest of amines, is at least as effective (though less specific) 

 than the complex organic bases studied by Macintosh and Paton (Schild, 1949). 







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Fig. 44 



On closing the circuit a wave of ' exploding' mast cells spreads from the negative pole to the 

 centre of the field, and stops. If the current is reversed the remaining half of the field is 



similarly affected. 



The violent disruptive effect of ammonia on the mast cells was demonstrated 

 in vivo by exteriorizing a loop of small intestine from a rat under Nembutal 

 anaesthesia and spraying the peritoneal window with warm ammonia vapour. 

 Here the disruption of the living mast cells can be seen under the microscope 

 (Fig. 46). Such a preparation can be used for examining the effects of the less 

 toxic liberators, applied topically or injected intravenously into the rat. 



Two small series of animals were given intraperitoneal injections of sodium 

 hydroxide, or ammonium hydroxide (West, 1956) and estimations were subse- 

 quently made of the tissue histamine, as in the previous work in which compound 

 48/80 was used. The results are recorded in Tables XVIII and XIX. 



118 



