ANATOMICAL AND PSYCHIC LOCALISATION 263 



a way as to indicate that its associative memory has 

 not suffered through the operation. But if the an- 

 terior parts of both hemispheres be removed, the dog 

 is no longer normal, but idiotic. It no longer reacts 

 in the same way it did before, and it is obvious that 

 its associative memory has suffered. The same is true 

 if both posterior halves of the cerebral hemispheres be 

 removed (2, V.). 



If we ask at present what determines this difference, 

 we are at a loss to give an answer. We might point 

 out that the right and left hemispheres are practically 

 symmetrical, while the anterior and posterior parts 

 are not symmetrical. If the form or orientation of 

 the elements be of importance, we might conceive of 

 the possibility that in a brain with only one cerebral 

 hemisphere all the processes could occur in approxi- 

 mately the same form, while in the brain with both 

 posterior or both anterior halves of the hemispheres 

 gone, the processes of association could not be re- 

 peated in the same, but in a mutilated form. Hence 

 the idiocy which follows such operations. We might 

 illustrate this by an analogous experience in the phy- 

 siology of sound. Each vowel is determined by a 

 sound of a certain pitch. If a singer sings in a pitch 

 higher than that of the determinant, the vowel becomes 

 indistinct. It is possible that in the brains of the 

 above-mentioned dogs the associations are rendered 

 impossible or difficult, because certain elemental pro- 

 cesses are no longer possible. 



3. In this connection I may mention that the bo- 



