602 COMPARATIVE PHYSIOLOGY. 



mals, seen to be the most involved and important of the whole 

 — a fact which the results of disease of the brain are well calcu- 

 lated to impress, inasmuch as interruptions anywhere among a 

 class of cerebral connections, now known to be very extensive, 

 suffice to abolish voice, and especially speech-production. 



Among mammals below man the vocal bands and laryngeal 

 and thoracic mechanism are very similar, but less perfectly 

 and complexly co-ordinated ; so that their vocalization is more 

 limited in range, and their tones characterized by a quality 

 which to the human ear is less agreeable. Man's superiority as 

 a speaking animal is to be traced chiefly to the special develop- 

 ment of his cerebrum, both generally and in certain definite 

 regions. 



