2 Material and Methods of Examination [CHAP. 



Rainhill Asylum that, in a large proportion of cases dying insane, all the microscopic methods 

 at our disposal will fail to disclose changes, either in the nerve cells or fibres, which we 

 can refer to their altered mental condition ; and that in other cases in which the mental 

 disorder is more advanced or of a graver nature, while we may be able to discover alterations 

 in the nerve cells, thanks to the marked advance which has been made of late years in 

 this province of histology, yet the present state of our knowledge will not allow us to make 

 any definite declaration concerning attendant changes in the nerve fibres. And I am able 

 to speak without reservation of the difficulties which beset the detection of morbid changes 

 in the nerve fibres in the cerebral cortex, because for several years prior to the inception 

 of the present investigation I devoted much time to a study of this subject. I am 

 of course well aware that in grave forms of mental disease, such for instance as general 

 paralysis of the insane, the fibres undergo serious alterations, but in choosing material for 

 this work I have naturally avoided such cases and been careful to select individuals in whom 

 the mental disorder was one of the simpler forms unaccompanied by other disease of the 

 nervous system ; in whom the attack of insanity had not been of longer duration than one 

 month ; who prior to its onset had given evidence of average intellectual ability ; whose 

 final illness was not associated with prolonged failure of general nutrition ; who were of 

 standard physical development and free from deformity, and whose brains were up to the 

 average weight, free from wasting, and in every respect normal to the naked eye. Such 

 brains I have obtained from cases of puerperal insanity and simple mania, and to prove 

 that they form safe material for investigation, I have carefully compared the sections of them 

 with those of the normal brain and satisfied myself that no obvious differences exist to 

 invalidate the results and certainly nothing that would deter one from using them restrictedly, 

 as in mapping out the general distribution of the various types of arrangement of nerve fibres. 



B. Normal Comparative Material. 



1. Right cerebral hemisphere of a Chimpanzee, completely examined for nerve 



fibres and partially investigated for nerve cells. 



2. Left hemisphere of a Chimpanzee (another animal), completely examined for 



fibres only. 



3. Right hemisphere of an Orang, completely examined for fibres only. 



For these anthropoid brains I am indebted to Professor C. S. Sherrington of Liverpool. 

 They were taken from animals previously utilised by that gentleman in his experimental 

 researches (in collaboration with Professor Griinbaum) on the motor area in the higher apes, 

 and it has been satisfactory to find that the delicate method of electrical excitation employed 

 in stimulating the cortex in those researches has not in any way damaged the brains 

 for histological purposes. 



C. Pathological Material. 



Two brains from cases of Amyotrophic Lateral Sclerosis, seven from cases of amputation 

 of one or other extremity, three from cases of Tabes Dorsalis and one from a case of old- 

 standing capsular lesion were examined, in the manner described hereafter, to determine 

 certain points bearing on the functions of the central convolutions and parietal lobe ; and 

 the occipital lobe was completely examined in two cases of old-standing blindness. 



