S4l 



transmission by impulses might be proposed, which should 

 afford similar data for calculation as the received undulatory 

 theory ; and that the results of mathematical investigation 

 applied to such material or impulsive theory would also be 

 satisfactory : also that he was of opinion that many of the 

 effects of interference and polarization of light were phe- 

 nomena of vision, leading to inferences much at variance 

 with the undulatory theory. 



Henry Hartop, Esq., then described " The Geology of 

 the District of Wentworth," which paper will not be pub- 

 lished at present, as the Author is desirous of extending his 

 observations. 



At the request of the Chairman, Dr. Heaton then read 

 the following Paper : — 



ON THE MUTUAL RELATIONS OF ANIMAL AND VEGETABLE 

 EXISTENCE. BY J. D. HEATON, M.D., LEEDS. 



My object in this paper will be to point out some of the 

 various modes in which the continued existence and integrity 

 of each of the great kingdoms of organized nature are made 

 to be dependant upon the continuation of the same conditions 

 on the part of the other. To show how the animal races of 

 the present era are indebted to the agency of vegetable life 

 iu former geological epochs for the perfect adaptation of our 

 atmosphere, and of the superficial strata of the solid globe, 

 to their physical requirements; and how, by the mutual 

 reactions, and counteractive influences of plants and animals, 

 the atmosphere, the waters, and the more solid materials of 

 the surface of our planet, are now retained permanently in a 

 condition most exactly adapted to the necessities of both. 

 Thus evincing most clearly that animal, vegetable, and 



