( Ign?) 
insensitive external layers of the body, and are in contact 
with the nervous system in the interior. Of the senses 
of hearing and tasting we know remarkably little, though 
some good work has been done at them recently. I cannot, 
however, quit this part of my subject, without reminding you 
of the very interesting chapter in Sir John Lubbock’s book 
‘On the Senses of Animals,’ in which he deals with the question 
of unknown senses. If there should be any of you who have 
not read it, I should advise you to repair the omission as 
soon as possible. 
There is perhaps no word in the English language more 
vague in meaning than ‘instinct’: it is used with a variety 
of meanings attached to it, and frequently with almost 
no meaning at all. It is used by some to indicate their 
impressions as to the nature of the mental processes in 
insects or other animals; by some, as that condition which 
in animals replaces our own reason; while others use it 
simply as a term to be applied to a series of animal actions ; 
others impersonify it and give it an objective existence, as 
when they say, “‘ instinct teaches them ”’; and yet again, the 
word is in use by scientific men to indicate a certain limited 
class of our own actions. This latter is its primary use, and 
it ought also to be its sole use. The application of the word 
in Entomology gives rise to a great deal of confusion. I am 
not aware, however, that any terms have yet been proposed 
to replace it, and I shall to-night use it as meaning ‘‘ some 
connected series of insect actions.” 
There seems to be a widely spread impression, to the 
effect that instinct cannot be accounted for by any theory of 
evolution. 
M. Fabre has published, at intervals, three volumes of 
studies on the habits and instincts of insects: the second 
volume of the series was noticed at considerable length by 
Sir John Lubbock, in his presidential address to this Society 
eight years ago, and a third volume has been since published 
by the talented French naturalist. As an observer of the 
habits of insects, M. Fabre stands, I think, facile princeps 
in our generation: in literary ability he has never been 
surpassed, and rarely equalled by any writer on Entomology : 
