Pussy’s Olfactory Sense. 51 
receive by the sense of sight. The recurrence of these odours 
in their proper reverse order—every house, ditch, field, and 
village having its own well-marked individuality—would make 
it an easy matter for the animal in question to follow the 
identical route back, however many turnings and cross roads it 
may have followed. This explanation appears to me to cover 
almost all the well-authenticated cases of this kind.” 
With ali due deference to Mr. Wallace’s reputation as a 
naturalist—without question one of the very highest in an age 
of splendid achievements in science—I think this explanation is 
fatally assailable at a number of points. But it is not now my 
purpose to enter into a general discussion which would occupy 
a very considerable space. There is, however, so distinct an 
issue raised by the words, “its most acute and only available 
sense,” that this may be considered by itself with reference to 
the cat alone; and it appears to me to be fatal to Mr. Wallace’s 
theory—at least in the case of that animal. Most people must 
have been struck with a suspicion of the deficiency of the sense 
of smell in cats, as I was myself long before I took any mea- 
sures for ascertaining what its extent might be. Immediately 
on reading Mr. Wallace’s letter, I thought it must have very 
doubtful application to cats, whatever might be the case with 
dogs. Accordingly, I made some experiments, which revealed 
to me a surprising and unsuspected deficiency in pussy’s olfac- 
tory sense. These J transcribe from the copy of a letter which 
I wrote to the late Dr. Charles Darwin, who took a keen interest 
in the discussion then being carried on. 
“T do not know whether you will consider this a crucial’ 
experiment as to the comparative acuteness of the sense of 
smell in dogs and cats, but perhaps it may be useful in adding 
one fact to the discussion on the part played by this sense in 
guiding animals home. I have long had reason to think that 
the sense of smell in cats is much less highly developed than in 
dogs and even many other animals, because, among other things, 
we see the difficulty cats often seem to experience in finding 
food thrown down to them, unless they see it fall, bobbing their 
E2 
