The occasional occurrence of small olfactory bulbs in the albino rat has been noted by Holt,1 Sugita2 and Donaldson and Hatai3 and in my previous study.4 These bulbs, which occur rather infrequently in young rats and which were designated as stunted by Sugita, were found to be present in all the senile rats studied.4 The fact that the decrease in volume was apparently dependent on the loss of the entering olfactory fibers led me to obtain some further material in order that the olfactory mucous membrane and olfactory nerves might be studied along with the olfactory bulbs. The results of this study form the basis of the present communication.
MATERIAL AND METHODS
Twelve male albino rats of the experimental colony strain were obtained from the Wistar Institute for this investigation. These were of the same stock as those used in a previous study and like them were all normal rats