358 NEKVOUS SYSTEM. 



Longet, that " one cerebral liemispliere in a healthy con- 

 dition may suffice for the exercise of intelligence and the ex- 

 ternal senses." In support of this statement, Longet cites 

 several cases of serious injury of one hemisphere without 

 impairment of the intellect. 1 



Another very important point, which we believe had 

 never before been noted, is brought forward very strongly 

 by Dr. Hammond. In what is called the ataxic form of 

 aphasia, the idea and memory of words are intact, and there 

 is simply loss of speech from inability to coordinate the mus- 

 cles concerned in articulate language. Patients affected in 

 this way cannot speak, but can write with ease and correct- 

 ness. In the amnesic form of the disease, the idea and 

 memory of language are lost ; patients cannot speak, and are 

 affected with agraphia, or inability to write. In cases in 

 which hemiplegia is marked, the aphasia is of the ataxic 

 form ; while in cases in which there is no hemiplegia, the 

 aphasia is amnesic. 



" The gray matter of the lobes presides over the idea of 

 language, and hence over the memory of words. When it 

 only is involved, there is no hemiplegia, and there is no dif- 

 ficulty of articulation. The trouble is altogether as regards 

 the memory of words. 



66 The corpus striatum contains the fibres which come from 

 the anterior column of the spinal cord, and is besides con- 

 nected wuth the hemisphere. A lesion, therefore, of this 

 ganglion, or other part of the motor tract, causes paralysis 

 of motion on the opposite side of the body. The cases I 

 have detailed show, without exception, that the power of 

 coordinating the muscles of speech is directly associated 

 with this hemiplegia. A lesion, therefore, followed by hemi- 

 plegia and ataxic aphasia, indicates the motor tract as the 

 seat. If amnesic aphasia is also present, the hemisphere is 

 ikewise involved." a 



1 LONGET, Anatomic et physiologic du systeme nerveux, Paris, 1842, tome i., p. 

 666, et seq. 2 HAMMOND, op. cit., p. 217. 



