In an attempt to clarify the formation of neutrophile granules, electron microscopic studies have been made on the granulocytes in the bone marrow cf mouse and rabbit.
In myelocytes and metamyelocytes, an active formation of neutrophile granules occures. Terminal endings of the Golgi lamellae extend irregularly into the cytoplasm surrounding Golgi area. Electron dense materials appear in various forms, such as dumb-bell, short rod, oval and round, and also varied sizes. It is considered that the cut surfaces of the Golgi endings on the way of granule formation must take the above mentioned shapes. Consequently, the process of granule formation can be traced morphologically by reconstructing the pictures, appearing on the cut surfaces.
Thus it is concluded that neutrophile granules ars produced in the endings of Golgi lamellae in the simillar ways as in the secretary granules of the secretory cells like pancreas, exocrine and endocrine cells. The granular substances accumulate at the ending of Golgi lamella, grow into round electron dense particles, and finally drop off from the Golg lamellae and scatter diffusely into cytoplasm.
Acid phosphatase activity may be seen in both Golgi lamellae and in some neutrophile granules, showing the properties analogous to lysosome.