50 Precentral or Motor Area [CHAP. 



the occurrence of retrograde degeneration of the central portion of the divided neurone is 

 an invariable and necessary sequence, but also the change in these cases is on all foul's with 

 that which affects the anterior cornual nerve cell and the central portion of the peripheral 

 nerve standing in connection with it, after a section such as occurs in an amputation ; 

 the only difference being, that in the latter instance we have to deal with an interruption 

 of the second instead of the first link in the neurone. 



We have now to enquire whether the retrograde degeneration, initiated in the second 

 neurone by section of the peripheral nerve, can overstep the anterior cornual cell, and, 

 proceeding along the primary neurone to the cortex, cause degeneration of the presiding 

 body ; in other words, whether, in the case of the cortical motor element, suppression of 

 the discharge of energy which it elaborates, by division of the second link in the neuronic 

 system, results in corporeal disintegration. I think we can prove that it does. 



So far as I am aware, Acquisto and Pusateri, working in conjunction, and Peli are 

 the only observers who have recorded positive po.st-amputation changes in the cortex cerebri, 

 and as their findings are of great importance, I shall quote their cases. 



(1) Acquisto and Pusateri's case concerned a man, aet. 48, who 29 years previously 

 had had his left thigh amputated through the upper third. Serial sections of the central 

 convolutions do not seem to have been made, but a careful microscopic examination re- 

 vealed the following changes : " In tutte le sezioni appartenenti al terzo superiori delle 

 circonvoluzioni rolandiche di destra, notavansi delle alterazioni notevoli nel terzo strato della 

 corteccia cerebrale. Le grandi cellule piramidali erano in grandissima parte scomparse, rari 

 erano gli element! superstiti." 



" Di questi alcuni si presentavano normali, in altri invece, e questi erano in maggior 

 numero, notavasi un iatto assai caratteristico. Per lo piu nella parte basale della cellula 

 osservansi delle grosse zolle formate da globuli giallastri fittamente stipati gli uni agli 

 altri di aspetto vitreo (vescicole globulari di Colucci). In corrispondenza di queste vescicole 

 globulari e per un certo tratto attorno ad esse la sostanza cromatica presentavasi disgre- 

 gata in piccoli granuli mentre era normale in tutto il resto del corpo cellulare." 



In this description it will be observed that no reference is made to the cells of Betz, 

 but I take it that the " grandi cellule piramidali nel terzo strato " are their equivalents. 



(2) The second case is quoted by Acquisto and Pusateri but is from the pen of 

 Peli, another Italian. It is stated that it showed confirmatory changes. 



Now although not so fully recorded as one would wish, these cases suffice in the first 

 place to indicate that post-amputation alterations may arise in the cortex, and I can now 

 remove all doubt on the point by stating in positive terms and from my own experience 

 that changes do occur. For during the past few years I have obtained and examined the 

 brains of seven individuals, disabled for a varying period of time by amputation of one 

 or other extremity, and in none have I missed finding microscopic changes, akin to, if not 

 absolutely identical with those to which Marinesco has given the name "reaction a distance." 



Not satisfied with the mere discovery of the cortical change, I have proceeded further 

 and exercising every caution mapped out its exact distribution, as a result of which I am 

 now able to advance some evidence which is specially valuable in enabling us to effect 

 a differential or divisional localisation in the motor area, evidence which at any rate 

 enables us to put our finger on the spot where the cells for the control of arm and leg 



