PREFACE. 
xi 
individual cases. However, I should like to add in this 
connection that it does not follow, because I have only 
quoted a small percentage of the letters which 1 have re- 
ceived, that all of the remainder have been useless. On 
the contrary, many of these have served to conyey infor- 
mation and suggestions which, even if not reserved for 
express quotation in my forthcoming work, have been of 
use in guiding my judgment on particular points. There- 
fore I hope that the publication of these remarks may 
serve to swell the stream of communications into a yet 
larger flow. 1 
In all cases where I have occasion to quote statements 
of fact, which in the present treatise are necessarily 
numerous, I have made a point of trying to quote 
verbatim . Only where I have found that the account 
given by an author or a correspondent might profitably 
admit of a considerable degree of condensation have I 
presented it in my own words. 
And here I have to express my very special obligations 
to Mr. Darwin, who not only assisted me in the most 
generous manner with his immense stores of information, 
as well as with his valuable judgment on sundry points 
of difficulty, but has also been kind enough to place 
at my disposal all the notes and clippings on animal 
intelligence which he has been collecting for the last forty 
years, together with the original MS. of his wonderful 
chapter on 4 Instinct. 5 This chapter, on being re-cast f;; 
the 6 Origin of Species, 5 underwent so merciless an amour 
of compression that the original draft constitutes a rich 
store of hitherto unpublished material. In my second 
work I shall have occasion to draw upon this store more 
largely than in the present one, and it is needless to add 
1 Letters may be addressed to me directly at 18 Cornwall Terrace, 
Regent’s Park, London, ISI W. 
