x] Frontal n<l rnfrotifaf Arm* -'-3 



beside the angle of the lower jaw on the left side, and emerging at the sagittal structure, 

 did not prove fatal but changed an intelligent and industrious artisan into an altogether 

 depraved being 1 . 



As this disturbance seems to be such a well-established result of frontal lesion it would 

 be extremely interesting to learn with exactitude the extent of cortex or the nature of the 

 tracts on the destruction of which it depends; above all things I am curious to know 

 whether obliteration of my " prefrontal " area and its relations would suffice for the change, 

 or whether it is necessary for the lesion to extend into the " frontal " area, but these of 

 cuurse arc questions to which a reply is at present impossible. Indeed our general 

 knowledge of the real functions of the frontal lobes is in an extremely unsatisfactory 

 condition. 



KM KKYOLOGK 'A I, 1 >ATA. 



As with other fields so again here it is interesting to compare the results bearing on 

 territorial demarcation which I have obtained with the results arrived at by Flechsig. 



So far as I have observed Flechsig does not indicate in any of his schemes a sub- 

 division of this part into fields corresponding with my "frontal" and "prefrontal" areas, but 

 while he appears to classify the whole area as pertaining to terminal regions, " that is, regions 

 acquiring their medullated fibres later than one month after the normal period of birth," 

 one gets the impression from his figures of 1898 and later publications, showing by numbers 

 the succession of myelinisation in different parts of the cortex, that he might have done so ; 

 at any rate he might have so divided the cortex on the mesial surface of the hemisphere; 

 because in his 1898 figure (I only take this for convenience, the others are similar), the 

 number 1 is placed in the paracentral lobule over what I take to be the mesial annex of 

 the " precentral " or perhaps the " postcentral " area, it is a matter of no consequence ; 

 proceeding forwards the number 9 falls close to the middle of my " intermediate precentral " 

 area; next over the part which I would call "frontal" the figures 17 and 17 a occur, while 

 in the pregenual region and also by the way on the orbital surface (all part of my " pre- 

 frontal " area) the figures 36, 37 and 40 are scattered. But as I have indicated the agreement 

 cannot be carried satisfactorily over the lateral surface ; it is true that Flechsig's figures 17 

 and 17 a again lie in my "frontal" area, Flechsig also excludes the inferior frontal con- 

 volution, or at least the major part of it, from his terminal regions (10 is placed on the 

 orbital operculum, which most anatomists include in the inferior frontal gyrus), and so far 

 we are in unison, but in regard to the middle frontal gyrus we fall out, for the numbers 

 30 and 36 occupy cortex which I believe to be of the " frontal " type and very different 

 from that over which Flechsig's other high figures are placed. Yet taking everything into 

 consideration it cannot be denied that there is a strong suggestion of correspondence between 

 Flechsig's findings and mine, and this in itself is a point of interest. It is also instructive 

 to find that the highest number in Flechsig's series, 40, is placed on parts of the " prefrontal " 

 area, showing that in his opinion it is the last to myelinate. 



1 Faihire of memory, hebetude, apathy, vague indifference, somnolence, and inability to concentrate the attention 

 have all been described as accompaniments of frontal tumour or abscess, but these are likewise manifestations of 

 increased intracranial pressure, and may arise in cases of tumour, etc., far away from the frontal lobe. The 

 disturbances of smell and sight which have been reported are admitted to be extraneous effects, and the form of 

 atnxia described by Bruns has been attributed to pressure exerted backwards on the cerebellum in the line of thrust. 



312 



