AS TO THE HEttEDlTT OF ACQUIRED CONDITIONS. 493 



(9) Gowers * has described the condition of the brain in a case 

 of congenital absence of one hand. The subject was a mah', 

 aged 40, who was born without a left hand. The forearm bones 

 were well developed, but at the extremity there was only an 

 irregular mass of bone consisting apparently of the two rows of 

 carpal bones, very imperfectly developed and anchylosed together 

 except at one point. In the brain there was a marked difference 

 between the two ascending parietal convolutions. At their origin 

 at the longitudinal fissure, for the first inch of their extent, they 

 were nearly equal in size, and continued nearly equal fc^r the 

 upper 1| inches. In the next (middle) two inches there Avas 

 a very marked diff'erence, the right being a narrow single convo- 

 lution, and the left broad and depressed by a slight secondary 

 sulcus. This occupies precisely the area, stimulation of which, 

 according to the experiments of Eerrier upon monkeys, causes 

 movements of the opposite hand. It is, of course, impossible to 

 say whether the brain or the hand defect was the primary one. 

 The following remark of the author, however, renders it possible 

 that the former may have been the cause : — " I am not aware 

 that the brain has been examined in any similar case. In several 

 instances, in cases of old amputations of the arm, an atrophy has 

 been found, but it has been slight, and has not been uniformly 

 localised." 



These facts, I think, render it probable that the nervous 

 system exercises more influence upon the course of deve- 

 lopment than has been hitherto attributed to it. It is true that, 

 on the opposite side, it may be urged that aneucephalous foetuses 

 are fairly well developed and are yet without brain. To this it 

 may be replied — 1st, that the development is more apparent than 

 real, since the bodies of such foetuses are always overloaded with 

 fat, a condition which, as we have seen, follows upon loss of nerve 

 influence ; and 2nd, that we do not know the date at which the 

 disease occurs which causes the defect. Certainly it is later than 

 the period at which tlie eyes are fully formed. It may be that 

 the disease does not occur until after development has proceeded 

 sufficiently far to proceed with the remnants of nerve system which 

 exist. It must not be forgotten that these forms sometimes live 

 and breathe for a short time, showing the existence of some im- 

 portant parts of the nervous system. 



As regards the kinds of malformations most likely to follow 



* 'Brain; Oct. 1878. 



