Meynert traced an enormous division of the crus directly to the frontal lobe and the lenticular nucleus, and showed that this portion through the transverse fibres of the pons was of necessity connected with the cerebellum, and that far other functions are to be located in the cortex than merely muscular innervation, visual and auditory perceptions. The restiform columns derived from spinal fibres enter the cerebellum and terminate chiefly in its hemispheres. The cortex of these hemispheres is connected by radiatory fibres, with the dentated nucleus, which is a recipient of fibres of the auditory nerve. The cortex of the cerebellar hemisphere receives fibres both from the sensorial periphery of the body and the semicircular canals. From this reception area the transverse fibres of the pons originate and enter the crus. It is these which enter the frontal lobe and lenticular nucleus. In no respect does man so much differ from the ape as in the quantitative development of these fasciculi. Their development is intimately associated with the mass of the frontal lobe, and there is every reason for considering them the channel of information of the equilibrium and possibly of the senses of space and time, on which the scope of the mind is so closely dependent. Lesions in these tracts may disturb these sensations, and the entire mental architecture may totter with the withdrawal or weakening of so important pillars. The congenital asymmetry of the peduncular tracts observed in certain cases of mental and moral perversion are not without bearing on the symptoms of those cases. And this explanation would be adjunct to the principle of mal-development of the associating tracts here advanced in explanation of other symptoms of these same states. It is a logical truism that complex cerebral functions have a complex substratum. Nothing could be more unphilosophical, for example, than to speak of "intellectual cells" (Denkzellen) in the cerebral cortex. Simple elements can have but simple functions; complex functions require a union of numerous simpler elements in a complex structural combination. Such symptoms as epileptic explosions are admittedly connected with no demonstrable anatomical aberration, and yet when epileptic explosions of a certain type are found associated with a cortical lesion they are to be regarded as symptoms of that lesion. Morbid projects, delusions, and moral perversion are simply functional perversions of a properly built cerebral mechanism or the outcome of a visible structural defect. And when the latter is palpably attributable to an error in development and occurs with a certain constancy in similar cases, a fundamental relation must be assumed between the defect and the general tenor of the symptoms.