5 i8 TEXT-BOOK OF PHYSIOLOGY. 



After a few days the symptoms partially subside and the animal 

 acquires the power of sitting on the abdomen when the anterior 

 limbs are widely extended (Fig. 233). As the days go by the improve- 

 ment continues, and the animal recovers the power of walking, though 

 each step is attended with tremor and oscillations of the body. Any 



FIG. 232. ATTITUDE ASSUMED AFTER DESTRUCTION OF THE LEFT HALF 

 OF THE CEREBELLUM. (Moral and Doyen, after Thomas.) 



change in the center of gravity such as results when one leg is lifted 

 may result in a fall toward the side of the lesion, owing to an 

 inability to promptly bring about the necessary compensatory 

 muscle actions. With time the animal continues to improve in its 

 power of adjustment, though it never completely recovers it. Move- 

 ments of progression are apt 

 to be characterized by stiffness 

 and accompanied by tremor 

 suggestive of volitional efforts. 

 Total removal of the cere- 

 bellum is followed by a differ- 

 ent train of symptoms. The 

 extensor muscles apparently 

 preponderate in their action, 

 for the limbs are extended 

 and abducted, the head and 

 neck are retracted, and opis- 

 thotonos is established. In 

 time these effects also partially 

 subside, though all attempts 

 at walking are permanently 

 accompanied by tremor and oscillations. The characteristic effect 

 which follows section of the peduncles is again incoordination, 

 manifesting itself in deviation of the head, eyes, inability to walk, 

 tremor on exertion, etc. The effects vary, however, according to the 

 peduncle divided. Section of the middle peduncle gives rise to the 

 most pronounced effects. The head and the anterior part of the 

 body are at once drawn toward the pelvis on the side of the section. 



FIG. 233. ATTITUDE IN REPOSE AFTER 

 THE COMPLETE REMOVAL OF THE 

 CEREBELLUM BUT DURING THE 

 PERIOD OF RESTORATION OF FUNC- 

 TION. (Moral and Doyen, after 

 Thomas.} 



