LETTER XLV. 
SENSES OF INSECTS. 
AT first one would think that the senses of insects 
might be described in very few words, and scarcely af- 
ford matter for a separate letter; but when we find that 
physiologists are scarcely yet agreed upon this subject, 
and that the use of some of their organs, which appear 
to be organs of sensation, has not yet been satisfactorily 
ascertained — we shall not wonder that it requires more 
discussion than at the first blush we were aware of. In 
treating on this head I shall first say something on the 
senses in general, and then confine myself to those of 
insects. 
Touch, taste, smell, hearing, and sight, I need not tell 
you, is the usual enumeration of the senses : but as the 
term includes every means of communication with the 
external world, the list perhaps might be increased ; and 
there is ground for thinking that the number seven, so 
signalized as a sacred number a , may also here have 
place. Dr. Virey, an eminent physiologist, whose sen- 
timents on various subjects I have before noticed with 
approbation b , appears to be of opinion that there are 
a Vol. III. p. 15. note \ b Ibid. 58-. See above, p. 26. 
VOL. IV. ' R 
