124 



THE MECHANISM OF LIFE 



T halo. us 

 From cortex 



through the superior peduncles and putting the cerebellum in 

 communication with the mid-brain, and so with the organs of 



special sense. The 

 vestibular part 

 of the auditory 

 organ that is, 

 the part which 

 is known experi- 

 mentally to be 

 concerned in the 

 maintenance of 

 equilibrium and 

 posture of the 

 body has also 

 direct nervous 

 connection with 

 the cerebellum. 

 The receptors in 

 the deeper 

 muscles and 

 joints are con- 

 nected with the 

 cerebellum by 

 special tracts (see 

 Fig. 31), and 

 there are also 

 descending tracts 

 connecting this 

 part of the brain 

 with the motor 

 nuclei of the 

 spinal cord. Even 

 the nuclei of the 

 cranial nerves are 



eereb'ellvm 

 ho cord. 



Skin 



FIG. 36. THE CONNECTIONS OF THE CEREBELLUM. 



Impulses pass up from the skin, muscles, joints, etc., 

 into the cerebellum, via I, the inferior, and S, the 

 superior peduncles. From the cerebellum impulses connected with 

 pass to the thalami and red nuclei, and from the 

 latter efferent impulses pass down into the cord. 

 The cerebellum is also connected, via M, the middle 



the cerebellum. 

 It is known 



peduncle, with the cortex, and in other ways, not also, from direct 



shown in the diagram, with the organsof special sense. 



experiments, that 



injuries to, or even removal of, the cerebellum leads to no obvious 

 impairment of sensation, and yet the organ has most conspicuous 



