Page:Principles of Psychology (1890) v1.djvu/55

Rh followed months later by contracture of the muscles, as in man after inveterate hemiplegia. According to Schaefer and Horsley, the trunk-muscles also become paralyzed after destruction of the marginal convolution on both sides (see Fig. 7). These differences between dogs and monkeys show the danger of drawing general conclusions from experiments done on any one sort of animal. I subjoin the figures given by the last-named authors of the motor regions in the monkey's brain.



In man we are necessarily reduced to the observation post-mortem of cortical ablations produced by accident or disease (tumor, hemorrhage, softening, etc.). What results during life from such conditions is either localized spasm, or palsy of certain muscles of the opposite side. The cortical regions which invariably produce these results are homologous with those which we have just been studying in the dog, cat, ape, etc. Figs. 8 and 9 show the result of