184 FRAGMENTS OF SCIENCE. 



adjustment continues; a slight bulging out of the epi- 

 dermis over the pigment-granules supervenes. A lens 

 is incipient, and, through the operation of infinite ad- 

 justments, at length reaches the perfection that it dis- 

 plays in the hawk and eagle. So of the other senses; 

 they are special differentiations of a tissue which was 

 originally vaguely sensitive all over. 



With the development of the senses, the adjust- 

 ments between the organism and its environment grad- 

 ually extend in space, a multiplication of experiences 

 and a corresponding modification of conduct being the 

 result. The adjustments also extend in time, covering 

 continually greater intervals. Along with this exten- 

 sion in space and time the adjustments also increase in 

 speciality and complexity, passing through the various 

 grades of brute life, and prolonging themselves into the 

 domain of reason. Very striking are Mr. Spencer's 

 re-marks regarding the influence of the sense of touch 

 upon the development of intelligence. This is, so to 

 say, the mother-tongue of all the senses, into which 

 they must be translated to be of service to the organism. 

 Hence its importance. The parrot is the most in- 

 telligent of birds, and its tactual power is also greatest. 

 From this sense it gets knowledge, unattainable by 

 birds which cannot employ their feet as hands. The 

 elephant is the most sagacious of quadrupeds its tac- 

 tual range and skill, and the consequent multipli- 

 cation of experiences, which it owes to its wonderfully 

 adaptable trunk, being the basis of its sagacity. Feline 

 animals, for a similar cause, are more sagacious than 

 hoofed animals, atonement being to some extent made 

 in the case of the horse, by the possession of sensitive 

 prehensile lips. In the Primates the evolution of 

 intellect and the evolution of tactual appendages go 

 hand in hand. In the most intelligent anthropoid apes 



