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THE POPULAR SCIENCE MONTHLY. 



given to the world is probably the most 

 trustworthy and instructive that has yet 

 been contributed to that science. There has 

 been a copious literature of anecdote de- 

 signed to illustrate the mental capacities of 

 the most intelligent members of the animal 

 series as the dog, the elephant, the monk- 

 ey, and the ant; but while, on the one 

 hand, the statements have often been so ex- 

 travagant as to awaken incredulity, on the 

 other there has been but little exposition of 

 principles which would enable the reader to 

 judge of the truth or error of current repre- 

 sentations. The interest in the subject has 

 always been great, and, with the prevailing 

 lax habits of criticising evidence, many sto- 

 ries have passed into circulation, and been ac- 

 cepted, which would hardly bear examina- 

 tion. It was eminently desirable, therefore, 

 and for scientific purposes imperative, that 

 the popular statements should be rigorously 

 sifted, in order that we may find out what 

 may be relied upon as true. It is obvious 

 that only the thoroughly prepared psycholo- 

 gist is competent for such work, and many 

 years of study in this field have well quali- 

 fied Mr. Romanes to undertake it. 



The present volume is in a certain sense 

 complete in itself ; and from another point 

 of view it is but a foundation, which is yet 

 to have its superstructure. It has long been 

 the author's intention to write a treatise 

 upon comparative psychology, in the light of 

 the doctrine of evolution, and his intention 

 was to treat the whole subject in a single 

 work. His preliminary inquiry was, of 

 course, into the facts upon which such a 

 view must rest, but he found his materials 

 so extensive, and in themselves so impor- 

 tant, that he was compelled to arrange for 

 two separate books ; the first to be made up 

 of the observed facts, carefully collated and 

 classified, so as to give the grades of intelli- 

 gence actually reached in the various groups 

 of the animal kingilom, and to leave for a 

 second volume the problem of psychical de- 

 velopment to be derived from these data. 

 The present book on " Animal Intelligence " 

 is the first, and is mainly descriptive, while 

 the second, to be built upon it, will be more 

 analytic and philosophic. 



Undoubtedly the present volume will 

 have the highest interest for general read- 

 ers, as it involves no speculation or abstruse 



reasoning, and aims only at descriptions 

 and discriminating estimates of the degree 

 of intelligence manifested in the different 

 groups of animate creatures. 



But while Mr. Romanes has closely sift- 

 ed his materials, so as to furnish only au- 

 thenticated facts, it would be a great mis- 

 take to suppose that his pages are less en- 

 tertaining than the loose compilations with 

 which we have been familiar upon this sub. 

 ject. The phenomena are equally surprising 

 and wonderful, but with the further advan- 

 tage that we have a fair confidence in their 

 reality. The intelligence displayed by the 

 inferior animals is often well calculated to 

 awaken astonishment, and we are free to 

 confess that some of Mr. Romanes's stories 

 would excite incredulity if we had not a 

 pretty strong confidence in his caution, and 

 if the special manifestations alleged were 

 not confirmed by other and similar observa- 

 tions. To the general reader, the book will 

 prove a fund of interest on one of the most 

 fascinating of subjects, and to the student 

 of natural history it will have a scientific 

 value as affording a sound basis for the for- 

 mation of conclusions respecting the psychi- 

 cal capacities of animals. 



In regard to the vexed question of mind 

 and instinct in the lower animals, of which 

 so much has been written, the author lays 

 down at the outset the principle that he will 

 follow in determining mental gradation, and 

 this may be gathered from the following re- 

 marks in his introduction : 



" The criterion of mind, therefore, which 

 I propose, and to which I shall adhere 

 throughout the present volume, is as fol- 

 lows : Does the organism learn to make new 

 adjustments, or to modify old ones, in ac- 

 cordance with the results of its own indi- 

 vidual experience ? . . . I may, however, 

 here explain that in my use of this criterion 

 I shall always regard it as fixing only the 

 upper limit of non-mental action ; I shall 

 never regard it as fixing the lower limit 

 of mental action. ... In other words, be- 

 cause a lowly-organized animal does not 

 learn by its own individual experience, we 

 may not therefore conclude that, in perform- 

 ing its natural or ancestral adaptations to 

 appropriate stimuli, consciousness, or the 

 mind-element, is wholly absent ; we can only 

 say that this element, if present, reveals no 



