Age and Nitrogen Content of Rabbit Brain Parts

¹ From the Thudichum Psychiatric Research Laboratory, Galesburg State Research Hospital, Galesburg, Illinois

The nitrogen content of whole rabbit brain and seven areas, thereof, i.e. frontal cortical gray, caudate nucleus, superior colliculi, medulla, paraflocculi, vermis and lateral lobes, has been determined using 230 rabbits ranging in age from 1–70 days. In general, the percentage wet weight nitrogen content of the cerebellar areas reached a higher maximum than did that for the noncerebellar areas studied. The nitrogen of whole brain rose steadily until the 50th day of age at which time it reached a plateau. In comparing the various areas it was found that with the exception of the colliculi the phylogenetically older parts reached their maximum percentage nitrogen content at an earlier age than did the more recent areas.