Kempf adds to the vast store of data on Abraham Lincoln a consideration of certain organic factors which he believes adds to the understanding of Lincoln's character and behavior. Based on an examination of the Volk life mask, photographs, and various biographical data, Kempf holds that Lincoln suffered a fracture of the skull over the left eye resulting from the kick of a horse at the age of ten. This led, the author adduces, to cerebral damage, both direct and contrecoup. The organic cerebral and visual involvement interacted with the emotional factors and traumata which were present in his life to produce his inclination to melancholia, from which he 'protected himself by cultivating a practical, common-sense philosophy of humanism and humor'.