PKEFACE. 
vii 
not a doubt that, for the present generation at all events, 
no subject of scientific inquiry can present a higher 
degree of interest; and therefore it is mainly with the 
view of furthering this inquiry that I have undertaken 
this work. It will thus be apparent that the present 
volume, while complete in itself as a statement of the 
facts of Comparative Psychology, has for its more ultimate 
purpose the laying of a firm foundation for my future 
treatise on Mental Evolution. But although, from what I 
have just said, it will be apparent that the present trea- 
tise is preliminary to a more important one, I desire to 
emphasise this statement, lest the critics, in being now 
presented only with a groundwork on which the picture is 
eventually to be painted, should deem that the art dis- 
played is of somewhat too commonplace a kind. If the 
present work is read without reference to its ultimate 
object of supplying facts for the subsequent deduction of 
principles, it may well seem but a small improvement 
upon the works of the anecdote-mongers. But if it is 
remembered that my object in these pages is the mapping 
out of animal psychology for the purposes of a subsequent 
synthesis, I may fairly claim to receive credit for a sound 
scientific intention, even where the only methods at my 
disposal may incidentally seem to minister to a mere love 
of anecdote. 
It remains to add a few words on the principles which 
I have laid down for my own guidance in the selection and 
arrangement of facts. Considering it desirable to cast as 
wide a net as possible, I have fished the seas of popular 
literature as well as the rivers of scientific writing. The 
endless multitude of alleged facts which I have thus been 
obliged to read, I have found, as may well be imagined, 
excessively tedious ; and as they are for the most part re- 
corded by wholly unknown observers, the labour of reading 
