SENSE AREAS AND ASSOCIATION AREAS. 205 



(It is a curious fact that Bouillaud's observations were inspired by the work 

 of Gall. Gall having observed, as he thought, that individuals who are fluent 

 speakers or who have retentive memories are characterized by projecting eyes, 

 concluded that this peculiarity is due to the larger size of the lower part of the 

 frontal lobe, and he therefore located the faculty of speech in this region of the 

 brain. In spite of the vagaries into which he was led by his false methods Gall 

 made many most important contributions to our knowledge of the anatomy of 

 the brain and the cord. The discovery of the location of the center of speech, 

 however, cannot be rightly placed to his credit, since his reasons for its location 

 were, so far as we know, entirely unjustified. It cannot be reckoned as more 

 than a coincidence that in this particular his phrenological localization was 

 afterward in a measure justified by facts.) 



The essential truth of Bouillaud's observations was established 

 by other observers, and Broca especially located the part of the 

 brain involved in these lesions in the posterior part of the third or 

 inferior frontal convolution. This region is, therefore, frequently 

 known as Broca's convolution or Broca 's center. Subsequent ob- 

 servations have abundantly confirmed this localization, and what 

 is designated as the " speech center" is placed in the inferior frontal 

 convolution in the gyrus surrounding the anterior or ascending 

 limb of the fissure of Sylvius (S, Fig. 92.) Moreover, autopsies have 

 shown that in right-handed persons this center is placed or is func- 

 tional usually in the left cerebral hemisphere, while in the case of left- 

 handed individuals aphasia and paralysis are produced by lesions 

 involving the right side of the brain. This region is not the direct 

 cortical motor center for the muscles of speech. It is possible that 

 aphasia may exist without paralysis of these latter muscles. It 

 is rather the memory center of the motor innervations necessary 

 to form the appropriate sounds or words with which we have learned 

 to express certain concepts. The child is taught to express certain 

 ideas by definite words, and the memory apparatus through which 

 these associations are transmitted to the motor apparatus may 

 be conceived as located in the speech center. Lesions of any kind 

 affecting this area will therefore destroy more or less the ability to 

 use appropriately spoken words, and clinical experience shows that 

 motor aphasia may be exhibited in all degrees of completeness and 

 in many curious varieties. The individual may retain the power to 

 use a limited number of words, with which he expresses his whole 

 range of ideas, as, for instance, in the case described by Broca,* 

 in which the individual retained for the expression of numbers only 

 the word three, and was obliged to make this word do duty for all 

 numerical concepts. Other cases are recorded in which the patient 

 had lost only the power to use names that is, nouns (Marie) 

 or could remember only the initial letters. Others still in which 

 words could be used only when associated with musical memories, 

 as in singing. It does not seem to be certain whether or not, in 



* Exner, "Hermann's Handbuch der Physiologic," vol. iii, part n, p. 342. 

 Consult for older literature. 



