EVOLUTION AND DISSOLUTION. 175 



commonest variety of hemiplegia, we say that there is loss of more or 

 fewer of the most voluntary movements of one side of the body ; we 

 find that the arm, the more voluntary limb, suffers the more and 

 longer ; we find, too, that the most voluntary part of the face suffers 

 more than the rest of the face. Here Ave must speak particularly of the 

 lower level of evolution remaining ; strictly we should say collateral 

 and lower. We note that, although unilateral movements (the more 

 voluntary) are lost, the more automatic (the bilateral) are retained. 

 Long ago this was explained by Broadbent. Subsequent clinical re- 

 searches are in accord with his hypothesis. The point of it is that the 

 bilateral movements escape in cases of hemiplegia in spite of destruc- 

 tion of some of the nervous arrangements representing them ; the 

 movements are doubly represented — that is, in each half of the brain. 

 Hemiplegia is a clear case of dissolution, loss of the most voluntary 

 movements of one side of the body with persistence of the more auto- 

 matic movements. 



3. The next illustration is paralysis agitans. Apart from all specu- 

 lation as to the seat of this disease, the motorial disorder illustrates 

 dissolution well. In most cases the tremor affects the arm first, begins 

 in the hand, and in the thumb and index-finger. The motorial disor- 

 der in this disease becomes bilateral ; in an advanced stage paralysis 

 agitans is double hemiplegia with rigidity — is a two-sided dissolution. 



4. Next we speak of epileptiform seizures which are unquestion- 

 ably owing to disease in the mid-region of the brain (middle motor 

 centers). Taking the commonest variety, we see that the spasm most- 

 ly begins in the arm, nearly always in the hand, and most frequently 

 in the thumb or index-finger, or both ; these two digits are the most 

 voluntary parts of the whole body. 



5. [The next illustration was by cases of temporary paralyses 

 after epileptiform seizures.] 



6. Chorea is a disease in which the limbs (the most voluntary 

 parts) are affected more than the trunk (the more automatic parts), 

 and the arms (the more voluntary limbs) suffer more than the legs. 

 The localization of this disease has not been made out ; symptomati- 

 cally, however, it illustrates dissolution. Chorea has a special interest 

 for me. The great elaborateness of the movements points to disease 

 " high up " — to disease on a high level of evolution. Twenty years 

 ago, from thinking on its peculiarities, it occurred to me that some 

 convolutions represent movements — a view I have taken ever since, 



7. Aphasia. This well illustrates the doctrine of dissolution, and 

 in several ways. We will consider a case of complete speechlessness : 

 (a.) There is loss of intellectual (the more voluntary) language, with 

 persistence of emotional (the more automatic) language. In detail 

 the patient can not speak, and his pantomime is of a very simple kind ; 

 yet, on the other hand, he smiles, frowns, varies the tones of his voice 

 (he may be able to sing), and gesticulates as well as ever. Gesticula- 



