1887.] -L-LJ [Claypole. 



results seems to be the want of the usual vigor, probably in consequence 

 of arrested development or of imperfect ante-natal nutrition — two of tlie 

 most fruitful sources of variation. 



2. Variation in strength. — It comes within the observation of all that 

 among animals great difference of bodily strength exists. This is easily 

 noticed in those that are reared for draught. Though less conspicuous the 

 fact is equally true of the savage species. Now this deficiency of power 

 is prejudicial to the variate. The load which one horse can draw with ease 

 is a severe tax on another. A battle between two wild beasts is decided, 

 other things being equal, to the injury and often the death of the 

 weaker. Indeed the prejudicial effect ensuing upon bodily weakness is so 

 evident that Jong proof is superfluous. 



Nor is the deficiency of mental power any less prejudicial. Every one 

 accustomed to observe animals must have noted great difierence in their 

 intelligence. Among domesticated species one individual shows mental 

 power fully entitled to the name of reason, while another, perhaps of the 

 same brood, manifests so little that education is impossible. A well- 

 known horse-trainer once told me that though he never failed to train a 

 horse when he took him in hand, yet there were but few that he could 

 train at all, and that he could, in a very short time, pick out and reject 

 the many with which success would be impossible. Some rats are so 

 cunning that to catch them requires all the craft and skill of the house- 

 holder. Others are so silly that they walk into the trap the first time it is 

 set, and are killed to their great prejudice. The sagacity of bears in 

 avoiding the snare is sometimes wonderful, compelling the belief that they 

 have mastered its construction and found out how to take the bait and yet 

 avoid the danger. Others show no subtlety of this kind, and are caught 

 and killed with ease. Such tales may be found in any work on the habits 

 of animals, and need not be repeated here. But enough has been said to 

 show that the range of variation of the mental faculties of animals is 

 great, and that while the higher degrees confer much advantage on their 

 possessors, the lower are so far inferior as to be seriously prejudicial. 



Though pertinent to the argument, it is scarcely worth the time to point 

 out the frequent occurrence of similar prejudicial variation in the human 

 species where the range of the mental faculties is from idiocy upward. 

 In our present state of civilization this disadvantage is partially and 

 temporarily neutralized by the humane sentiment prevailing in society 

 which counteracts the laws of natural selection as they operate among 

 other animals. Yet all such deficiency of power is seriously and often 

 fatally prejudicial 



3. Variation in the senses. — Whatever prejudicial effect ensues from de- 

 ficiency of bodily or mental strength is aggravated when this deficiency 

 takes the form of the absence of one or more of the senses. Yet animals 

 are not infrequently born blind or deaf, and the probable reason wliy 

 such cases are seldom seen is that the absence is so prejudicial as to be 

 soon fatal. 



