1869.] 



On the Structure of the Cerebral Hemispheres. 



5] 



The equivalents that have heen deduced from only one compound, or of 

 which the different determinations are not fairly accordant, are marked? 

 in the above Table. 



The specific refractive energy of a body is in some respects worthy of 

 more consideration than the refraction-equivalent, since, being only the 

 refractive index minus 1 divided by the density, it is a physical property 

 independent of chemical theories as to the atomic weight. Among 

 suggestive facts are noticed the extreme energy of hydrogen ; the existence 

 of pairs of analogous elements having the same, or nearly the same, energy, 

 — as bromine and iodine, arsenic and antimony, potassium and sodium, 

 manganese and iron, nickel and cobalt ; and that among the metals capable 

 of forming soluble salts there is some connexion between their power to 

 saturate the affinities of other elements, and their power to retard the rays 

 of light. 



XXV. <c On the Structure of the Cerebral Hemispheres." By "W . 

 H. Broadbent, M.D., Lecturer on Physiology at St. Mary's 

 Hospital Medical School,, and Senior Assistant Physician to 

 the Hospital, Physician to the Fever Hospital. Communicated 

 by F. Sibson, M.D. Received June 17, 1869. 



(Abstract.) 



The object of the investigation has been twofold. First and chiefly, to 

 endeavour to ascertain minutely the course of the fibres by which the con- 

 volutions of the hemisphere are connected with each other and with the 

 crus and central ganglia. 



Secondly, to endeavour to ascertain whether there is a constant similarity 

 between the corresponding sides of different brains as compared with the 

 opposite sides of the same brain; and should this be the case, to endeavour to 

 trace the relation between any anatomical difference which might be dis- 

 covered and such physiological difference as seems in the present state of 

 our knowledge to be indicated by the association of loss of the faculty of 

 language with disease of the left hemisphere rather than the right. 



The present communication relates almost exclusively to the first branch of 

 the investigation, and the method pursued has been to harden the brain by 

 prolonged immersion in strong spirit, by which the fibres are rendered per- 

 fectly distinct and fairly tenacious, so that with care and patience their 

 course and arrangement may be accurately ascertained. 



Previous researches on the structure of the cerebrum have been mainly 

 directed to the examination of the course and distribution of the fibres 

 radiating from the crus and central ganglia, which have been assumed or 

 supposed to occupy ultimately the axis of every convolution, the different 

 convolutions being connected by fibres which crossed under the sulci from 

 one to another. It is here shown that the commissural communication 



E 2 



