THE MAST CELLS 



It has been known since the time of Ehrlich that, in course of development, 

 mast cells make their appearance late in embryonic life or early in infancy. 

 Comparison was therefore made between the histamine and mast-cell contents 

 of similar organs from foetal or very young mammals and from fully developed 

 adults (Table VI). In every case the low values for histamine in the young 

 organs contrasted with the higher values in adults. Apart from the presence or 

 absence of mast cells, no other obvious histological difference was noted between 

 the pairs of tissues which were examined. 



It is therefore concluded from this study of the normal tissues of many 

 species that there does exist a strong positive correlation between the density 

 of the mast-cell population in a tissue and its histamine content. 



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