ON THE FUNCTIONS OF THE CEREBRUM 345 



mental degeneracy ; but all grades exist, from individuals who 

 may be regarded, in their normal condition, as " sane," to others, 

 of greater cerebral degeneracy, who are never really so. In such 

 cases the cerebrum, as regards its lower complexes, is " racing " ; 

 and, in the more degenerate types, objective signs of generally 

 aberrent and sub-normal cerebral activity are permanently in 

 evidence. 



On the other hand, cases are common in which, from toxaemia 

 of the cortical neurones and consequent pathological conditions of 

 these elements, all grades and types of temporary or permanent 

 maiming of the processes of cerebral association are existent. 

 Such patients exhibit what is described as " mental confusion." 

 The earliest evolved and most stable parts, i.e. the projection 

 spheres, are the least affected, and hence the patients are able 

 to receive sensory impressions in a more or less normal manner. 

 The later evolved zones of lower association (and especially the 

 latest evolved centre of higher association) are, however, more 

 seriously affected, and hence the patients make frequent mistakes 

 with regard to the identifying of sensations, suffer from halluci- 

 nations, and may exhibit any type and grade of defective com- 

 prehension and any symptom of " aphasia." In such cases the 

 cerebrum is temporarily or permanently maimed owing to lesion 

 of its constituent elements. 



Though examples of abnormal cerebral activity of the immediate 

 type might be multiplied to any extent, those given above will 

 suffice to indicate that our knowledge of the higher functions of 

 the cerebrum, though still in its early stages, does not depend 

 solely on histological, neuro-pathological, and experimental data, 

 but may derive illumination and illustration from the study of 

 mental disease. 



A number of recent papers of interest will now be referred to. 



The mechanism and localisation of the psychic processes has 

 formed the subject of a recent paper by Jendrassik. This writer 

 denies the existence of an " association centre," on the ground that 

 the connections between memory images are not actual paths but 

 occur through a " tuning " of associated images, with the result that 

 if one of these is evoked the images in harmony with it are also aroused 

 into consciousness. His theoretical discussion is rather unsatisfactory, 

 but the deduction may be readily drawn that he considers association 

 to be a process, and the psychic products, which are evolved as results 



