SPEECH 313 



object. The same processes must be working when he 

 himself speaks or \vrites the name of the object. In such 

 a comphcated process as this it is clear that the brain 

 must act as a whole. Nevertheless there appear to be 

 certain regions of the brain which seem to be specially 

 concerned in the production of the spoken and written 

 word. 



In 1863, Broca showed that loss of speech was produced 

 by lesion of the third frontal convolution on the left 

 side in right-handed and on the right side in left-handed 

 people. These patients have lost the power of articulation. 

 They can express themselves in writing and can hear a,nd 

 understand what is said to them and what they read. 

 This condition is known as motor aphasia, and the centre 

 which is diseased is known as the glosso-kinsesthetic centre, 

 for it is the area supposed to be concerned in the sensation 

 of the position and movement of the tongue. It was 

 pointed out, however, by Marie that aphasia may occur 

 without demonstrable lesion of this area. He beheves 

 that in the cases quoted by Broca the lesion was not 

 hmited, as was supposed, but involved subcortical fibres 

 in such a way as to interrupt impulses coming from other 

 parts of the cortex. Marie beheves that there is no 

 locahsation of speech. In a sense this is true, but it might 

 be expected that the power of speech would be more 

 intimately associated with those areas of the brain con- 

 cerned in the reception of images. Of these there are 

 two — the auditory and the visual. The former is the 

 centre concerned in the reception and storage of auditory 

 words ; it is situated in the temporal lobe. The latter is 

 concerned similarly with visual words, and is situated in 

 the occipital lobe. Above Broca's area, too, is an area 

 in which the sense of movement of writing is said to be 

 located. This area is adjacent to the part of the motor 

 area devoted to the hand. It is therefore to be ex- 

 pected that a disturbance of any of these centres may 

 cause loss of speech, and there is a certain amount of 



