histamine: pathological tissues 



to an active lesion of the generalized type and in a series of samples of normal 

 skin obtained from patients undergoing operations to breast or abdomen. 

 These normal values agree closely with the figures published by Nilzen (1947)- 

 The results of the present investigation are set out in Table VII. 



Table VII 



Mast cells and histamine in norma/ human skin and in skin lesions of urticaria pigmentosa 



of varying extent 



The above results thus strongly support the view that the histamine value 

 in human skin varies directly with its mast-cell content. 



Mast-cell tumours from domestic animals 



Dogs (See: Cass et al, 1954). A subcutaneous tumour-like collection of 

 mast cells, so-called mastocytoma, has for long been recognized as a rare 

 condition which occurs almost exclusively in dogs (Murray, 1908; Bloom, 1942) 

 though solitary examples have been reported in a horse (Sabrazes and Lafon, 

 1907), a cat (Sabrazes, Muratet and Antoine, 1908) and a cow (Greig, 1950). 

 Oliver, Bloom and Mangieri (1947) used such a tumour from a dog to prove 

 that a powerful anticoagulant (heparin) can be extracted from the mast cell. 

 We, in turn, have employed mastocytomas from dogs, cats and cattle to show 

 that not only does the mast cell contain heparin; it is also extraordinarily 

 rich in histamine. 



However, various difficulties were found to lie in the way of implementing 

 this programme of estimating histamine in mast-cell tumours from animals, 

 though once the necessary channels for obtaining material had been established 



79 



