Distribution of Fluorescing Islets, Adrenaline and Noradrenaline in the Adrenal Medulla of the Cat

In previous reports (Eränkö, 1951 a, b, 1952) it was shown that cell islets can be demonstrated in the adrenal medulla of the rat which differ histochemically from the other medullary cells. These islet cells are acid phosphatase negative and exhibit a bright autofluorescence after fixation in formalin, while in contrast to this, the other medullary cells are strongly acid phosphatase positive and fluoresce feebly after treatment with formalin. Both types of cells are morphologically similar and give a positive chromaffin reaction.