in support of an assertion of Aristotle. 509 



Zoology ; by attracting to the subject the attention of those 

 naturalists, who might be qualified, and at liberty, to determine 

 the points at issue, by a train of exact researches. 



I wished also to be an auxiliary, in the work of rescuing the 

 natural science of the Peripatetic sage, from the neglect and 

 obloquy, with which the cultivators of the Baconian philosophy, 

 in their just zeal for discarding some of the forms of empirical 

 ratiocination, attributed to Aristotle, have inadvertently and un- 

 deservedly regarded his physical treatises. In this work, many 

 distinguished naturalists are now engaged ; it has already been 

 aided in the pages of the Zoological Journal ; and if in the above 

 character I am allowed to serve, under the banners of a Cuvier, a 

 Ferussac, and a Macleay, I shall be amply rewarded for my 

 slight exertions in the cause. 



I remain, &c. 



E. W. Brayley, jun. 



70, Hatton Garden, Feb. 10th, 1826. 



P. S. On looking through a volume of the Philosophical 

 Magazine, since the proof of the foregoing paper was corrected 

 for the press, my eye glanced on a passage in a memoir on the 

 Eyes of Insects, by M. Marcel de Serres, in which they are said 

 to be '^ constructed so as to receive the images of objects by the 

 simple shock of the rays which these objects reflect ;" a supposition 

 very similar to that which I have advanced in the note at p. 507, 

 in explanation of what appears to be the analogue of sight in the 

 Gasteropoda, &c. ; except that M. de Serres seems to adopt, in 

 this instance, the Newtonian or corpuscular theory of light. How- 

 ever, after attentively perusing his elaborate memoir, and compar- 

 ing it with what Swammerdam and Cuvier have detailed on the same 

 subjects, I think we shall be justified in concluding, that this 

 theory, as far as regards Insects, is unfounded. It also appears 

 to me, that the structure of their eyes, as described by M. de 

 Serres, when illustrated by the light Dr. Wollaston has recently 

 thrown on the long agitated question of single vision with two 

 eyes, furnishes strong grounds for believing, contrary to what has 

 hitherto been supposed, that the means by which vision is effected 

 in Insects, and in the Vertebrated Animals, are essentially the same. 



