LoESER, Functions of tJie Frog s Brain. 365 



be offered that the neuron-complex, consisting of an afferent 

 path to and an efferent path from the cerebellum and the 

 ganglionic structures intervening, had lost important elements 

 and that thus the function of the whole neuron-complex had 

 been destroyed. This represents absence of normal impulses 

 and may explain the defects after cerebellar excision. It is, 

 however, impossible for the remaining neurons to make connec- 

 tions with other surrounding normal neurons and thus take up 

 part of the functions formerly possessed by the desfroyed 

 neuron-complex. There evidently was a slight trace of this 

 modification of impulses present two months after cerebellar 

 excision, since the position of the body and the condition of 

 the limbs had improved two months after the operation. The 

 fact that the condition of the body and limbs became worse on 

 stimulation, probably indicates that the modified paths were 

 fairly able to master the situation during rest but were not cap- 

 able of doing so during excitation. It has been observed in 

 many instances that stimulation brings out to their fullest ex- 

 tent the defects which are in part hidden by the vicarious ac- 

 tivity of the modified paths during rest. 



After unilateral cerebellar excision, the bilateral defects 

 were confined to the homonymous side. Uni- as well as bi- 

 lateral excisions of the cerebellum have shown that it does not 

 possess the function of maintaining the equilibrium or any intel- 

 lectual functions. The former function is located in the 

 medulla, and the latter — the small amount that the frog pos- 

 sesses — probably in the scantily developed cerebrum and in the 

 optic thalami. 



My conclusions regarding the cerebellum do not agree with 

 those of Steiner' who states that symmetrical removal of the 

 brain down to the medulla in the frog produced no changes in 

 the motor activity of the extremities. 



Bilateral excision of everything anterior to the medulla 

 shows that, although the croak and turning-over centers seem 



' Steiner, J. Untersuchungen iiber die Physiologic des Froschgehirns. 

 Braunschweig, 1885. 



