510 



mutual affinities of the " typical forms " of Foraminifera whose struc- 

 ture he has now elucidated ; and he sums up the evidence which his 

 examination of them has furnished in regard to the very wide range 

 of variation which seems especially to characterize this group, 

 avowing his conviction that the only classification of it which can 

 approach to a really natural arrangement, will be one founded upon 

 the idea of " descent with modification " as the means by which an 

 almost infinite variety of special forms has been evolved from a few 

 fundamental types. 



June 21, 1860. 

 Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. 



Frederick Augustus Abel, Esq., Thomas Baring, Esq., John 

 Frederic Bateman, Esq., Edward Brown-Sequard, M.D., Richard 

 Christopher Carrington, Esq., and Roundell Palmer, Esq., were 

 admitted into the Society. 



In accordance with notice given at the last Meeting, the Right 

 Honourable George Augustus, Earl of Sheffield, was proposed for 

 election and immediate ballot ; and the ballot having been taken, his 

 Lordship was declared duly elected. 



The following communications were read : 



I. " Experimental Researches on various questions concerning 

 Sensibility." By E. BROWN-SEQUARD, M.D. Communi- 

 cated by Dr. SHARPEY, Sec. R.S. Received May 24, 1860. 



The first question I propose to examine relates to the duration 

 of sensibility in parts of the body completely deprived of the circu- 

 lation of blood. 



This question has hitherto received but little attention from phy- 

 siologists. It is true that many experiments have been made to ascer- 

 tain how long sensibility remains in animals in which circulation is 

 stopped by the application of a ligature round the large blood-vessels 

 of the heart ; but I do not know of any special research upon the 

 duration of sensibility in a nerve in which there is a suspension of 



