1885.] molecular energy on an absolute scale. 321 



saltum from zero to some amount greater than the difference of 

 potential which can be established by the combined effect of 

 gravitation and the other energies of the system within the space 

 occupied by the molecule, one would suppose that dissociation 

 must occur and by the action of gravitation be rendered permanent 

 at least in part. 



(2) On the transit of Venus, Dec. 6, 1882. By J. B. Pearson, 

 D.D. 



The paper contains an account of the reduction of observations 

 made by Dr Pearson, with a calculation of the value of the Solar 

 Parallax, found by comparing these with the French observations. 



November 9, 1885. 

 Professor Foster, President, in the chair. 



The following communications were made to the Society : — 



(1) On Weissmanris New Theory of Heredity. By A. Sedg- 

 wick, M.A. 



(2) Suggestions with regard to the nervous system of the Chor- 

 data. By W. Bateson, B.A., St John's. 



Having in view the facts of the anatomy and development of 

 the Enteropneusta, and especially the condition of the delaminated 

 portion of nervous system which is connected with the skin by 

 median-dorsal chords, the author argued that 



(1) The nervous system of the chordata must have been from 

 the first an unpaired and "unsegmented" structure. 



(2) That its present origin by invagination must be secondary 

 to a primitive process of delamination. 



(3) That the difference of function between the dorsal and 

 ventral roots must have been primitive, the result of the physical 

 necessities of the case. 



If these suggestions be accepted, the nervous systems of the 

 lower chordata form a regular and progressive series. 



(3) On the nature of the Heart-Sounds. By F. J. Allen, M.A., 

 St John's. 



The difference between the two sounds of the heart may 

 be one of degree rather than of nature. Certain circumstances 

 render the sounds more alike, and certain others increase their 

 difference. 



