ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 693 



be the vestibule-spinal tract. The nucleus fastigii of the cerebellum 

 has neuraxons passing down to the vestibular nucleus, which is con- 

 nected with Deiters, and these nuclei send neuraxons down the antero- 

 lateral columns to end in the anterior horns. 



In addition to the tottering walk and vertigo, deep lesions of the 



cerebellum in man produce a tendency to vomiting. This is probably 



due to the irritation which spreads to the center of the origin of the 



vagus nerve in the underlying medulla oblongata. Sometimes there 



is found a disposition to dyspnoea and syncope for the same reason. 



frequently there are changes in the organ of sight, as amaurosis, 



trabismus, and astigmatism. 



MIDDLE PEDUNCLES. Deep lesion of the middle peduncles of 

 ie cerebellum (those which pass to the pons Varolii), if made upon 

 me side only, produces in the animal a tendency to turn or rotate 

 ipon the principal axis of its body. If the lesion occur in the pos- 

 jrior part of the peduncle the rotation is toward the side where the 

 peduncle is cut. The animal may make as many as sixty or more 

 revolutions per minute. The rotation will be toward the opposite side 

 when the anterior portion of the peduncle has been injured. This 

 rotation is explained by Schiff, who admits paralysis of the rotary 

 muscles of the head and one side of the spinal colum. 



Cutting the middle cerebral peduncle brings on internal strabis- 

 ms in the eye on the side operated upon, but external superior stra- 

 bismus in the eye upon the opposite side. 



Lesion of the inferior peduncle of the cerebellum or of the bulb 

 >mes painful. Also the animal falls upon the opposite side and is 

 lable to keep itself erect. The animal's body is curved in the form 

 an arch toward the side of the lesion. 



Lesion of the superior peduncle does not give characteristic and 

 nse phenomena. 



The Pons. The pons represents a crossed way of conductibility 

 itween the periphery of the body and the brain, and vice versa. 

 Besides it is a coordinating center of -the actions that pass through* 

 le pons Varolii, at its anterior surface, shows itself to be but very 

 little or not at all irritable. Posteriorly, there are signs of great 

 tin and agitation in the animal under stimulation. Deep irritation 

 mses convulsions and pains according to the kind of fibers irritated. 

 ie facial nerve is often found paralyzed upon the same side as the 

 }ion and so opposite to the paralysis of the members and trunk, 

 lis condition is spoken of as alternate hemiplegia. 



The pons Varolii is the center of epileptiform convulsions. Deep 



