442 PHYSIOLOGY CHAP. 



and if forced to move, she fell to the right, owing to the limbs 

 of the right side, in which muscular and cutaneous sensibility 

 were altered, giving way. If thrown into water in a pool, she 

 swam properly with eyes open or blindfolded, with well-coordinated 

 movements, but with the right side deeper in the water than the 

 left. She died from severe and repeated epileptic attacks, five 

 months after the second operation. When the brain was removed 

 from the body both lesions were found to be complete (Fig. 

 234, A, B). 



In this case the inability to stand upright and to walk, after 

 ablation of the motor zone on the side opposite that of the cerebellar 

 operation, was not complete and permanent. The partial re- 

 education of the animal, notwithstanding the marked alteration 

 in motility and sensibility of the right limbs, was undoubtedly 

 due to the compensatory function of the right motor zone, which 

 had been left intact. In other cases, in fact, when the animals 

 were deprived of half the cerebellum and both motor zones, we 

 obtained permanent loss, not only of maintaining the erect posture 

 and of walking, but of swimming also. 



The phenomena of cerebellar deficiency exhibited by the animal 

 with a half cerebellum, particularly in the limbs of the operated 

 side, must be analysed more accurately. Let us again refer to the 

 bitch from which the tracings in Fig. 233 were taken. 



Prior to the extirpation of the right half of the cerebellum 

 this animal had been trained to sit up for a long time on its hind 

 legs. After the operation it lost this power, and had not regained 

 it fourteen months later. When food was brought to the animal 

 and held above its head, it stood upright, but fell suddenly, owing 

 to the flexion of the right hind-leg. When it was made to draw 

 a weight tied to its tail, the greater expenditure of force required 

 in walking caused it to fall frequently to the affected side. When 

 a clamp was applied to the lobe of the left ear the animal tried to 

 remove it by appropriate movements of the left fore-limb ; but if 

 the same clamp was placed on the ear of the side operated on, the 

 animal never attempted to use the limb of that side, but contented 

 itself with vigorously shaking its head, which frequently caused it 

 to lose its balance and fall to the right. To these and other 

 similar phenomena of cerebellar deficiency we gave the name of 

 asthenia : muscular asthenia due to nervous asthenia, the direct 

 consequence of loss of the influence of the homolateral half of the 

 cerebellum. 



Othej; phenomena prove that this asthenia is always closely 

 associated with a definite diminution of the normal tone of the 

 muscles i.e. of the degree of their active tension during rest 

 which must exert a considerable influence on the contractions and 

 relaxations of the muscles, particularly as regards the form, degree, 

 and duration of these processes. 



