214 THE POPULAR SCIENCE MONTHLY. 



ANIMAL INTELLIGENCE.* 



By GEOEGE J. EOMANES. 



ANIMAL INTELLIGENCE is a subject which has always been of 

 considerable interest to philosophical minds ; but, as most of you 

 are probably aware, the interest attaching to this subject has of late 

 years been greatly increased by the significance which it has acquired 

 in relation to the theory of descent. The study of animal intelligence 

 being thus, without question, fraught with high importance to the 

 science of our time, in adducing before this illustrious assembly some 

 of the results which that study has yielded, I shall endeavor to treat 

 them in a manner purely scientific. I shall try, as much as possible, to 

 avoid mere anecdote, except in so far as it is desirable that I should 

 put you in possession of a few typical facts to illustrate the various 

 principles which I shall have occasion to expound. I shall seek to 

 render apparent the more important of the issues which the subject, 

 as a whole, involves, as well as the considerations by which alone these 

 issues can be legitimately settled. I shall attempt to state my own 

 views with the utmost candor ; and if I shall appear to ignore any ar- 

 guments opiDOsed to the conclusions at which I shall arrive, it will only 

 be because I believe those arguments to admit of easy refutation. And, 

 in order that my exposition may be suflSciently comprehensive, I shall 

 endeavor to point out the relations that subsist between the intelligence 

 of animals and the intelligence of man. The aim and scope of the pres- 

 ent lecture will therefore be to discuss, as fully as time permits, the 

 facts and the principles of Comparative Psychology. 



As human intelligence is the only order of intelligence with which 

 we are directly acquainted, and as it is, moreover, the highest order of 

 intelligence known to science, we may most conveniently adopt it as 

 our standard of comparison. I shall therefore begin by very briefly 

 detailing those principles of human psychology which we shall after- 

 ward find to be of the most essential importance in their bearings on 

 the subject which I have undertaken to discuss. 



When I allow my eyes to travel over this vast assembly, my mind 

 receives, through their instrumentality, a countless number of impres- 

 sions. So far as these impressions enter into the general stream of 

 my consciousness, they constitiite what are called perceptions. Sup- 

 pose, now, that I were to close my eyes, and to fix my attention on 

 the memory of some particular perception which I had just experienced 

 — say the memory of some particular face. This mental image of a 

 l^revious perception would be what is called an idea. Lastly, suppose 

 that I w^ere to analyze a number of the faces which I had perceived, I 



' An evening lecture delivered before the British Association at Dublin, August 

 16, 1878. 



