104 CONSCIOUSNESS AND SENSATION. 



of matter properties incomprehensible and of which 

 there is no evidence. But it is remarkable that 

 neither medicine nor surgery, nor experiments on 

 animals, have shown any difference of function 

 in the different parts of the hemispheres. Wounds 

 of the brain and limited spots of disease do not 

 vary in their symptoms according to the part of 

 the roof of the hemisphere attacked. I am not 

 forgetful of the remarkable phenomena of aphasia 

 nor the discoveries of Broca, but I have pointed 

 out elsewhere 1 that the connection between aphasia 

 and lesion of the brain external to the island of 

 Reil is best explained, not by reversion to the 

 doctrine of the divisibility of the hemispheres into 

 different organs, but by taking into account the 

 variety of processes required to go on consentane- 

 ously to produce speech, and considering the 

 interruption to the consentaneous action of the 

 hemispheres by interference with the fibres of 

 communication at the most central part of the 

 organ. 



It is not only in the case of speech but in all 

 the more complicated operations of thought that 

 the mind has to attend to different matters at 

 the same time, and it can well be imagined that 

 simultaneous and harmonious action of the brain- 



1 Medical Press and Circular, nth March, 1870. 



