x THE FOEE-BKAIN 627 



patient remains intact ; he understands what is said or read to 

 him, and remembers what he previously learned. His vocal 

 organs are also normal, but he is unable to speak, though he can 

 sing vocally, laugh, and express emotions by his voice. His 

 auditory and verbal images are preserved, along with visual 

 images of objects and the images of written words. He can also 

 write intelligently when the lesion is limited to Broca's con- 

 volution, and mimetic language is perfectly retained. Sometimes 

 he continues the use of Yes and No and a few other words, as 

 exclamations. Under certain emotional conditions, but not 

 always at will, he is able to enunciate words a proof that the 

 right hemisphere too is to some extent concerned with motor 

 speech, as maintained by Gowers. 



Broca's theory has been attacked in recent years by P. Marie, 

 who declares that Broca's convolution does not take part in any 

 way in the complex function of speech. To support this he 

 invokes a large number of clinical cases of motor aphasia with all 

 the symptoms we have described, in w r hich a post-mortem examina- 

 tion showed the left third frontal convolution to be absolutely 

 intact. He also cited a second clinical series in which motor 

 aphasia was absent, while examination revealed isolated destruction 

 of Broca's lobule. 



Marie's cases do not, however, invalidate Broca's theory. If 

 carefully considered, it will be found that they are not irreconcilable 

 with that theory, as was shown by Mingazzini (1908). 



Clinical experience teaches that more or less transitory motor 

 aphasia may be due to the shock or disturbing effect of a focal 

 lesion which indirectly affects the function of the elements of 

 Broca's convolution. Mingazzini records a case, observed by 

 Panegrossi, of a patient affected with paralysis of the right arm, 

 who for several days entirely lost his speech, though able to under- 

 stand questions ; he only began to articulate certain words clearly 

 a few days before his death. The autopsy revealed a softening in 

 the middle part of the pre-central convolution, while Broca's 

 convolution was intact. The functions of the latter were evidently 

 affected solely by circulatory disturbances, and oedema due to the 

 haemorrhagic focus, which was beginning to subside shortly before 

 the patient's death. 



In other cases the motor aphasia may be due to arteritis or 

 thrombosis of the arterial branches that supply Broca's con- 

 volution. In a case of right hemiplegia associated with motor 

 aphasia, Mingazzini and Marchiafava found on post-mortem 

 examination arteritis and partial thrombosis of the left Sylvian 

 artery, with an enormous red softening which involved the 

 lenticular nucleus, external capsule, and the pyramidal region of 

 the internal capsule, without disturbance of Broca's convolution on 

 either side. 



