In a recently published paper, which formed the conclusion of work begun in this laboratory by W. M. Kraus in 1922, we 1 were able to show the elongation of the human anterior horn cell in the course of ontogenetic development. These cells, which up to the fourth embryonic month have the shape of a globe, are finally elongated in adult man, and the caudocranial diameter is three times as large as the transverse diameter. We tried to explain this phenomenon by neurobiotactic influences of higher centers on the motor cells of the spinal cord and as an expression of gradually increasing intersegmental integration.
One might object to this theory and try to explain the elongated form by physical influences of growth, by the extension of the spine and by the action of gravity on erect man. In order to test the validity of such objections, examinations of spinal cords