668 GENERAL REMARKS 



in each variety of skull, and are not (see p. 638) distinctive of 

 either. A zone therefore bounded in front by a line drawn over 



same sense (Anat. Descript., I. c., and 2 de ed., Paris, 1845, torn. iv. p. 346) from having 

 noticed that in senile dementia the occipital lobes are much more atrophied than the 

 frontal. These arguments, like so many in the same sphere, are amenable to the ob- 

 jection that the atrophy in question may be merely a concomitant change, correlated 

 in the way of mal-nutrition with some other really causative change, without being 

 itself the first term in the series of evils. It is however by no means necessary to 

 shelter ourselves behind this suggestion, for few if any mental alienists would be found 

 to take this view at the present time. In the last edition indeed (1870, iii. 2, p. 454) 

 of Cruveilhier's Anatomic Descriptive I find the words ' C'est sur ces circonvolutions 

 occipitales que porte principalement 1'atrophie senile/ standing without note or com- 

 ment or inference in connexion with them, and the reference to Neumann is omitted. 

 But what is of much greater consequence is to find an authority with the vast 

 experience which Dr. J. Crichton Browne possesses (see West Eiding Lunatic Asylum 

 Reports, 1876, vol. vi. p. 218) averring that the exemption which the occipital lobes 

 on his showing enjoy from the lesions characteristic of the general paralysis of the 

 insane, is 'as it were only part of a wider immunity from visible pathological change* 

 which they enjoy 'in all varieties of chronic insanity,' inclusive (p. 178) of 'senile, 

 simple, and consecutive dementia.' Dr. Fox in like manner in his ' Pathological 

 Anatomy of the Nervous Centres,' 1874, p. 41, tells us that ' the posterior lobes are 

 less often affected than the middle, and hemorrhage there; seems to be of far less 

 serious import.' To these statements it may be well to add the following made by 

 Professor Schroder van der Kolk (Pathology and Therapeutics of Mental Diseases, 

 English translation by J. T. Kudall, Melbourne, 1869, p. 46), ' In insanity proper, in 

 cases of confusion of ideas, and of haughty insanity, I have always found the anterior 

 lobes of the brain suffering, but on the contrary in the melancholic and those who 

 condemned themselves with or without religious admixture, I have found the upper 

 and posterior parts of the lobes diseased, and that in the latter cases the understanding 

 often showed no traces of disturbance, inasmuch as the individuals judged correctly 

 and disputed acutely. The pathological affection limits itself then to the upper 

 and hinder parts of the lobes, and in the fore parts nothing abnormal is seen in regard 

 to colour, firmness, and connexion with the pia mater. In those who at last finished 

 with dementia I never found the anterior parts of the lobes intact.' Cf . also pp. 24, 

 41, 44, 59, 63J 93, I. c. 



Dr. Lelut, the author of a memoir ' Du developpement du crane dans ses rapports 

 avec celui de 1'intelligence/ published in the ' Gazette Medicale de Paris/ has been 

 referred to by M. Foville (Systeme Nerveux, 1844, p. 649) and by Virchow (Gesamm. 

 Abhandlungen, p. 916) as having shown that in the cases of idiots the greatest diminu- 

 tion of the skull takes place in the posterior part of its circumference. Neither of the 

 authors who refer to M. Lelut accept this conclusion ; and a reference to Professor 

 Marshall's paper in the Philosophical Transactions for 1864 (p. 543, pi. xxi, xxii, 

 xxiii), ' On the Brain of a Bush woman and on the Brains of two Idiots of European 

 Descent/ will show that the facts upon which it is based may very readily be over- 

 stated, the real state of the case as regards the brains of these idiots being that 'whilst 

 all parts have been more or less arrested, the frontal and occipital lobes have suffered 

 more than the temporal or parietal.' 



The comparative anatomy of the brains of men and apes shows that the occipital 

 lobes have a greater relative development in the lower than in the higher apes, 

 and it has been maintained by Dr. A. Pansch (De Sulcis et Gyris in Cerebris 

 simiarum et hominum, 1866, p. 25 ; Archiy fur Anthropologie, 1869, iii. p. 252) that 

 the ' operculum ' which bounds the parieto-occipital fissure posteriorly is to be considered 

 an upgrowth which is sometimes much diminished in the Anthropomorpha, and which 

 is only rarely to be seen, except rudimentarily represented, in man. In other words, 

 the external perpendicular or occipito-parietal fissure is a valley formed not by depres- 



