246 Considerations on Function [CHAP. 



The papers of Schaffer, to which I will next refer, deal with the medullated nerve fibres 

 of the cortex, and are based on what appears to have been a careful examination of a series 

 of complete sections of two hemispheres from cases of general paralysis, sections like those 

 which Kaes used in his research. And in both these cases Schaffer thought that the disease 

 fell very heavily on the " association " centres of Flechsig and left the " sensory " centres 

 of the same writer intact. Now these are topographic conclusions which are out of harmony 

 with those of Kaes, who has also examined a general paralytic brain in its entirety and 

 by the same process ; they have also been combated by Nissl, and I am sure that there 

 are many in this country familiar with the microscopic experience of the cortex in general 

 paralysis who will support Kaes and Nissl in stating that this disease is ubiquitous, instead 

 of topically distributed in the manner Schaffer supposes. Without seeing Schaffer's specimens 

 it is of course impossible for me to offer a criticism carrying any weight, but having read 

 both his papers carefully I cannot help thinking that some of my remarks made in criticising 

 Bolton's work can be reapplied. It will be observed that the parts which Schaffer believes 

 to have escaped disease are precisely those in which the fibre wealth and especially the wealth 

 of large fibres is greatest ; on the contrary, the parts most affected are those most poorly 

 endowed in this respect, and the point to be debated is whether or not Schaffer has been 

 too liberal in his application of the term normal. To me it seems that he has, for the simple 

 reason that these parts are so richly stocked with fibres that they mask conditions of disease 

 and so prevent accurate judgments on their normality, and especially is this the case when 

 the sections are of great thickness, as Schaffer's must have been. And I feel entitled to 

 an expression of opinion on this point because in addition to my experience of the normal 

 brain I have had the cortex of the general paralytic constantly under observation for the 

 past twelve years, and have repeatedly noticed how sections of these parts may show profound 

 changes when stained for the display of nerve cells, blood vessels, and neuroglia, and yet 

 almost nothing when stained for nerve fibres, and like remarks apply to changes in the same 

 centres in other diseases 1 . I repeat therefore that on account of this dense structure and 

 peculiar architecture it is exceedingly difficult t<> judge from an inspection of nerve fibres 

 only of the normality or morbidity of the fields of cortex which Schaffer has looked upon 

 as sound, and for the same reason it follows that comparisons become ineffectual and uncon- 

 vincing when the same parts are reached. 



I have digressed more than I intended to discuss these conclusions of Bolton and Schaffer, 

 but I have felt that it was important to take more than a passing notice of them, 

 because they might be converted into unsound capital by those, unpractised in histological 

 research, who are investigating the functions of the brain and particularly those of the 

 frontal lobe. 



DATA DERIVED FROM COMPARATIVE ANATOMY. 



Hitzig's acceptance of the frontal lobe as the centre for higher psychic faculties, because 

 in the phylogenetic tree the development of the intellect proceeds pari passu with that 

 of the frontal lobe, is so full of suggestion that we cannot be surprised at the number of 

 adherents it has won. 



Since the cortex investing the sulcus cruciatus in some lower vertebrates corresponds 

 structurally and physiologically to the " precentral " area of man, it is clearly seen how 



1 In cases of tabes dorsalis, amputation, sleeping sickness, optic atrophy, deaf mutism, porencephaly and even 

 progressive muscular atrophy the very positive cell changes which I have found in the cortex have never been 

 accompanied by equally striking fibre alterations. 



