Remarks on the determination and significance of the gray cell coefficient

The present paper has been written in reply to Shariff’s treatise “Cell Counts in the Primate Cerebral Cortex” and is intended primarily to compare Shariff ’s method of calculating the gray cell coefficient with that developed by myself. The concept “gray cell coefficient” was introduced by von Economo in 1925. By this he understands the ratio between a griseum of the central nervous system and the volume of the nerve cells contained in it. This is the following fraction: