ADDENDUM. 



FURTHER HISTOLOGICAL STUDIES ON THE LOCALISATION OF CEREBRAL 

 FUNCTION. THE BRAINS OF FELIS, CANIS, AND SUS COMPARED WITH 

 THAT OF HOMO. 



DURING the period which has elapsed since the Manuscript of the foregoing work was 

 presented to the Royal Society, my investigation has been extended to the brains of some 

 of the lower animals, and, with the sanction of the Royal Society, the results are offered 

 here in the form of an Addendum. 



PART I. 

 HISTOLOGICAL. 



The brains employed were those of the Cat (Felis Dotnesticus), the Dog (Canis Familiaris) and 

 the Pig (Sus Communis). The chief objects held in view throughout the investigation were as 

 follows : to strengthen the position I have taken up in regard to the localisation of different 

 functions in the human brain ; to assist the physiologist in the future performance of experiments 

 aiming at the elucidation of problems still obscure (it was for this special reason that I chose 

 the brains of common animals, like the dog and the cat) ; and to settle various points bearing 

 on cerebral homclogies, which the comparative neurologist has been unable to determine. 



Method of Examination. 



It is unnecessary to describe the method of examination in detail, as it is practically identical 

 with that previously adopted. The brains were converted into series of complete transverse sections, 

 and pairs of sections, taken at intervals of '5 mm., were stained alternately, one for nerve fibres 

 by the method of Wolters-Kulschitzky, the other for nerve cells by a modification of the method 

 of Nissl. So, for instance, in the cat's brain, which is 5 cm. long, the arrangement of the cortical 

 nerve fibres and the cell lamination have been examined, side by side, in a series of one hundred 

 sections, equidistant from one another. 



CORTICAL SUBDIVISIONS. 



The cortex of these animals is subdivisible histologically into areas to which I will assign 

 the following names : -* 



Crucial or Motor, 

 Postcrucial or Sensory, 

 Parietal, 

 Visual, 

 Ectosylvian, 

 Iambic, 

 Rhinic, 

 Extrarhinic, 

 Frontal. 



