THE CENTRAL NERVOUS SYSTEM 751 



For example, it is certain that the Rolandic area has 

 sensory as well as motor functions; and there are good 

 grounds for believing that the sensory fibres from the 

 muscles and the skin terminate here in arborizations which 

 come into contact either with those of the motor pyramidal 

 cells, or with those of intermediate cells which link them to 

 the pyramidal cells. 



Pathological evidence in man agrees, upon the whole, with 

 wonderful precision with the results of experiments on 

 animals ; and, indeed, before any experimental proof of the 

 minute and elaborate subdivision of the cortex had been 

 obtained, Broca had already, from the phenomena of the 

 sick-bed and the post-mortem room, located a centre for 

 speech in the left inferior frontal convolution, and Hughlings 

 Jackson had associated pathological lesions of the Rolandic 

 area with certain cases of epileptiform convulsions. 



Aphasia. In most persons the inferior frontal convolution on 

 the left side is concerned in the expression of ideas in spoken or 

 written language. It is even said that oratorical powers have been 

 found associated with marked development of this convolution (as 

 in the case of Gambetta, the French statesman). Words are, at 

 bottom, arbitrary signs by which certain ideas are expressed. The 

 power of intelligent communication by spoken or written language 

 may be lost : (i) by paralysis of the muscles of articulation or the 

 muscles which guide the pen ; (2) by inability to hear or see the 

 spoken or written word, i.e., by deafness or blindness ; (3) by inability 

 to comprehend the meaning of spoken or written language, although 

 sensations of hearing and sight may not be abolished that is to say, 

 by inability to interpret the auditory or visual symbols by which 

 ideas are conveyed ; (4) by inability to clothe ideas in words, 

 although the ideas conveyed by speech or writing may be perfectly 

 comprehended. Neither (i) nor (2) is considered to constitute the 

 condition of aphasia; (3) represents what is called amnesia, or 

 sensory aphasia ; (4) is aphasia in the ordinary restricted sense, or motor 

 aphasia. It is this last condition which is associated with a lesion 

 in the left inferior frontal convolution. The portion of the convo- 

 lution concerned is the posterior extremity, where it borders on the 

 fissure of Sylvius, and it either completely coincides with or largely 

 overlaps the centre for the movements of the tongue, lips, and 

 larynx concerned in articulation. In motor aphasia the patient 

 understands quite well what is said to him, and also knows quite 

 well what to reply, but the words necessary to express his meaning 

 do not come to him. He makes no answer whatever, or strings 

 together a series of words each correctly articulated but having no 



