440 



hand, the right ventricle can be dissected only in connexion with the 

 left. 



For these reasons the Lecturer is inclined to regard the left ven- 

 tricle as the typical one, and the right as a mere segment thereof; 

 and in further corroboration of this opinion, he referred to the shape 

 of the right and left ventricular cavities, as shown by casts of their 

 interior. The left always yields a beautifully finished and perfect 

 right-handed conical screw, while the cast of the right ventricle, 

 although it has the same twist, represents only an incomplete 

 portion. This statement was illustrated by a wax-cast of the ven- 

 tricles of the heart of a deer. 



In conclusion, the Lecturer remarked that the arrangement of the 

 fibres composing the ventricles of the mammalian heart, as he had 

 endeavoured to expose it, is characterized by comparative simplicity, 

 and harmonizes perfectly with what is known of the heart's move- 

 ments. 



[The matters touched on by the Lecturer are more fully treated of, 

 and the descriptions copiously illustrated by figures, in his Paper 

 entitled " On the Arrangement of the Muscular Fibres of the 

 Ventricular Portion of the Vertebrate Heart." By JAMES PETTI- 

 GREW, Esq. Communicated by JOHN GOODSIR, Esq., Professor of 

 Anatomy in the University of Edinburgh. Received Nov. 22, 1859.J 



April 26, 1860. 

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



The following communications were read : 



I. " Note on Regelation." By MICHAEL FARADAY, D.C.L., 

 F.B.S. &c. Received March 13, 1860. 



The philosophy of the phenomenon now understood by the word 

 Regelation is exceedingly interesting, not only because of its relation 

 to glacial action under natural circumstances, as shown by Tyndall 

 and others, but also, and as I think especially, in its bearings upon 

 molecular action ; and this is shown, not merely by the desire of dif- 



