THE MAST CELLS 



the thin liver capsule from a two-months'-old calf, in which the mast cells are 

 fewer and smaller (Fig. 7) and the histamine content per gram is less than in 

 the adult, gave a histamine value of 18 m±g. histamine base per cell. 



Mast cells and histamine in other species (See Riley and West, 1953) 



Once satisfactory evidence had been obtained for the localization of tissue 

 histamine in the mast cells of cattle it seemed desirable to see how far this 

 concept could be applied to the cellular location of histamine in the mast cells 

 of other species. 



Apart from the figures given by Jorpes (1946; and Table II) there is little 

 information in the literature about the heparin content of various tissues. A 

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

 of some of the tissues analysed by Holmgren and Wilander (1937) for ester 

 sulphates, these values being assumed by them to represent heparin if other 

 sulphate-containing mucopolysaccharides are absent, particularly the chon- 

 droitin sulphate of cartilage. The histamine values and mast-cell contents of 

 the liver of various species, estimated separately as capsule and parenchyma, 

 are given below (Table IV). It should be noted that the values for 'capsule' 

 of ox and cow liver in this table are the values originally obtained before the 

 method of obtaining clean samples had been devised. As mentioned above 

 (Table III), an enormous concentration of mast cells and histamine can be 

 achieved once the difficulties in removing and cleaning the capsule have been 

 overcome. In passing, it may be noted that Holmgren and Wilander also 

 obtained their highest values for ester sulphates (presumptive heparin content) 

 in ox liver capsule, a tissue which they described as a 'pure culture of mast 

 cells'. 



Table IV 



Histamine content ([J-g.lg. tissue) and the relative mast-cell 

 content of the liver of different species 



It will be noted from Table IV that only dog liver contains much histamine 

 in its parenchyma : this is in line with the rich mast-cell and heparin content of 

 the organ. Examination of the remaining species discloses that, in general, 



74 



