ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 68<) 



the upper part of the molecular, or external, layer, forming a net- 

 work of fibers. The basket cells have their dendrons extending into 

 the inner part of the molecular layer, while their neuraxons arborize 

 in a tuftlike manner, forming a "basket-work" about the cells of 

 Purkinje. The internal layer is made up of multipolar cells whose 

 neuraxons form the horizontal fibers in the external, or molecular, 

 layer. These horizontal fibers divide in a T-shaped manner, arbor- 

 izing about the dendrons of the cells of Purkinje. 



In the granular layer there are relatively large cells known as the 

 cells of Golgi; their neuraxons end in the nuclear layer, while their 

 dendrons lie in the molecular layer. 



Between the external and the internal layers we have the cells 

 of Purkinje, which are supposed to be the cells concerned in the pres- 

 ervation of equilibrium. The dendrons of the Purkinje cells occupy 

 the chief part of the external layer, and have little, clublike projec- 

 tions on them. The neuraxons of the Purkinje cells go into the in- 

 ternal layer, enter the external layer, and arborize about the dendrons 

 of the cells of the latter layer. 



From the white matter come fibers, perhaps from the spinal cord, 

 which on entering the granular and molecular layers have at their 

 terminations irregular thickenings ; hence called moss-fibers by Cajal> 

 ho believes that they conduct impulses to the granular cells. 



Another kind of fiber from the white matter, perhaps from the 

 spinal cord, goes through the granular layer into the molecular layer, 

 and, like a climbing plant, clings around the dendrons of the cells 

 of Purkinje, and is called the tendril fiber. 



Foster holds that impulses from the spinal cord or other parts 

 pass along the tendril fibers to the dendrons of the Purkinje cells and 

 by their neuraxons away from the cerebellum to other parts. But 

 other impulses may be carried by the moss-fibers to the cells of the 

 uclear layer. From here the impulse would be carried to the mole- 

 ar layer and spread along the bifurcating fibrils a long distance, 

 which would carry them to the dendrons of the Purkinje cells. At the 



ie time the arborizations of the just-mentioned bifurcating fibrils 

 ning in a longitudinal direction about the basket cells would affect 

 Purkinje cells in an indirect manner, and, since the neuraxon of 

 h basket cell bears baskets for several Purkinje cells, a number 

 these Purkinje cells would be "associated" in the same event. 



The cerebellum has a threefold grasp on the cerebro-spinal axis : 

 By the direct cerebellar tract and the vestibulo-spinal tract ; by the 

 form bodies and inferior cerebellar peduncles. 2. By the middle 



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