In this discussion of the cerebellum, an attempt is made to visualize the genesis of cerebellar functions. Realizing how far in the future definitive conclusions in this subject must be, I prefer to consider this communication as a study embodying certain of my present views, leaving my position still flexible and open to whatever modifications further investigations may dictate. Many difficulties have previously been encountered in reaching a solution concerning cerebellar functions. Indeed, it seems almost impossible to draw any comprehensive deductions regarding this question from all of the evidence at present available. Animal experimentation and clinicopathologic observation in mammals and man leave much to be desired. A vast amount of experimental work has been carried on without the necessary preceding morphologic understanding of the cerebellum, and the results, in consequence, have often confused rather than clarified the situation. By far the majority of workers in the past have directed