INSTINCT AND INTELLIGENCE. 5^5 



and that of the hill far over the valley of the Saline; from these shad- 

 ows you obstruct the rays of light, and from these glimmering rays 

 you begin to realize that these simple peojDle, who had advanced so 

 far as to have learned the use and value of salt, probably from the 

 herds of mighty animals that came to lap the water of the springs, or 

 to lick the salt-impregnated earth, had also learned that the sun dried 

 away the water and left the salt ; and as they could not take the sun 

 down into the valley to the water, they carried the w^ater to the sun ; 

 and here on this southern slope, which tlien, as it does now, caught 

 the first rays in early morning, its noonday beams, and evening kiss, 

 were ranged scores probably hundreds of these primitive vessels, in 

 which the sun, by its direct rays and heat-laden, southern breath, was 

 doing the work of evaporation, yet not unaided by man. Around in 

 every direction you find evidence of this, for every stone and there 

 are myriads has been through tlie fire. They have been heated to 

 redness and plunged into the brine. 



Now, you may say I am indulging my imagination. Well, be it 

 so. If I am, my imagination keeps within the bounds of possibility ; 

 while yours would endow these primitive people, whose only imple- 

 ments or tools seem to have belonged to the rude age of stone, with a 

 skill in handling them far beyond what we in this enlightened age 

 possess, with all our appliances. And you do this to give a color of 

 truth to an entirely imaginary process, not sustained by a single fact. 







mSTIJSrCT AND INTELLIGENCE.^ 



By W. K. BEOOKS. 



TO many persons the phenomena of instinct and intelligence in 

 animals seem irreconcilable with any theory of the evolution of 

 organisms through the action of natural causes, but the popular opin- 

 ion upon this subject has undergone a very considerable change within 

 the last half-century, so that the difficulty now presents itself and 

 finds expression in a much more manageable form than would have 

 been the case a few years since. 



With regard to instinct, we can easily see that if animals of a 

 given species are born with a constitutional tendency, or instinct, to 

 perform a certain action under certain circumstances, this tendency 

 may be improved and perfected by natural selection, provided favor- 

 able variations appear, and be inherited. If instinct varies in the 

 different individuals of a species, the struggle for existence wall result 



' A lecture from a course on " Biological Theories," delivered at the Johns Hopkins 

 University, January, 1877. 



