Abstract
The adrenal medullary cells of the common marmoset were studied histochemically in control and strychnine-injected animals. These cells contains only adrenaline as they are not reactive to potassium iodate or fluorescent to ultraviolet light, and they do not show a strong reaction after incubation in α-naphthyl acetate, acetylthiocholine and butyrylthiochohine. They also contain alkaline phosphatase and a small amount of adenosine triphosphatase, but lack acid phosphatase. A moderate stimulus with strychnine produces a reduction of the chromaffin reaction with a marked or total loss of alkaline phosphatase; with a stronger dose of strychnine, these cells lose almost all chromaffin reaction, while alkaline phosphatase persists either in equal on in larger quantity. The presence of alkaline phosphatase was related to the release of adrenaline.