130 THi: NKKVOUS SYSTEM AND ITS CONSERVATION 



goes, arc very sluggish. But this does not mean that they 

 were greatly dependent upon the organization of the 

 cerebrum; they can lie just as seriously affected if their 

 olfactory receptors are destroyed, the cerebrum remain- 

 ing intact. 



A frog is regarded as a higher animal than a fish. A 

 decerebrate frog, however, departs so slightly from a 

 normal one as to force us to conclude that here. as in the 

 fish, the cerebrum has no important influence on the be- 

 havior of the animal under the ordinary conditions of 

 life. It is commonly stated, however, that there are real 

 points of difference between normal and decerebrate frogs. 

 The latter are entirely able to swim and hop, but they 

 will not save themselves from death in a pan of water 

 when it is slowly warmed. 1 



The classic instance of the profound effects following the 

 removal of the cerebrum from an animal of high grade 

 was afforded by the experiments of Flomvns, in France, 

 early in the nineteenth century. He subjected pigeons 

 to the operation, which is rather a, simple one to perform 

 upon the bird. The descriptions which he gave have 

 been modified by modern students to make allowance for 

 the well-marked recovery of pigeons from the immediate 

 shock of the procedure. In this case, as in that of the 

 cerebellum, it is only the lasting consequences of the loss 

 that we have a right to emphasize. Observers have not 

 been wholly agreed concerning the nature of the deficiency 

 in all its details, but it seems safe to say that a pigeon 

 without a cerebrum gives no further sign of memory or 

 feeling. 



To see such a pigeon is an instructive experience, and 

 e-pecially when the spectator takes ;iccount of his own 

 emotional reaction. lie is likely to anticipate that he 



1 Burnett i American .Inuriial of I'hy-Molo^v. I'.M'J, x\\, SO) lias 

 oli-erved that dec-erel irate I'm"- definitely lack (lie p<>\\ IT .-houn l>y 

 the intact animal- to liecome "u-ed tn" certain pathways. A trace 

 <i! adaptation mi I he part of individuals to their .-urn HUH lilies .-crins, 

 therefore, to I,,, represented in the cerel>ral equipment of these 

 animals. 



