LoESER, Functions of the Frog s Brain. 369 



is behind the trigeminus group and if the brain anterior to this 

 group is removed, every reaction on the turning table ceases. 



The excision of everything anterior to and including the 

 greater part of the brachial plexus, proves, as Schrader ob- 

 served, that co-ordinated movements stop only because the 

 origin of the nerves of the front legs is destroyed ; that after re- 

 moval of the medulla, co-ordinated movements still remain, and 

 that the more nearer the section approaches the origin of the 

 brachial plexus, the more is co-ordination impaired. 



Table of Operations and Chief Results. 



I. Excision of one cerebral hemisphere. 



(a) During the first three days the animal jumps slightly toward the crossed 



side. 



(b) From four days to two and a half months, no deficiencies were noticed. 



II. Excision of both cerebral hemispheres. 



(a) During the first three days, bilateral slightly defective strength of the 



muscles and somewhat subnormal skin reflexes. 



(b) Later, to two and a half months, no deficiencies were observed. 



III. Unilateral removal of the thalamus. 



(a) During the first two weeks, 



(1) Voluntary movements rare. 



(2) Touch sensibility very defective. 



(3) Almost total blindness on the crossed side. 



(4) Crossed legs are weaker. 



(b) From three weeks to two and a half months afterwards, (i), (2), and (4) 



are slightly, but (3) is not at all improved. 



IV. Bilateral removal of the thalami optici, 



Causes these permanent deficiencies : 

 (i) Almost complete bilateral blindness. 



(2) Touch sensibility very much impaired. 



(3) Voluntary movements very rare. 



V. Unilateral removal of the lobus and thalamus causes, 



(a) From one half hour to two weeks, 



(1) Total loss of sight on the crossed side. 



(2) Forced straight-ahead movements. . 



(3) Abnormal retention of urine. 



(4) Reduction in voluntary movements and touch-sensibility. 



(b) From third week to two and a half months, (l) is unimproved, (2) is 



much improved unless the animal is excited, {3) is normal, and (4) 

 somewhat improved. 



VI. Bilateral removal of the lobi and thalami. 

 (a) From one half hour to three weeks, 



(i) Total blindness on both sides. 



