THE BELFAST ADDRESS. 481 



pigment-grannies supervenes. A lens is incipient, and, 

 through the operation of infinite adjustments, at length 

 reaches the perfection that it displays in the hawk and 

 eagle. So of the other senses; they are special differen- 

 tiations of a tissue which was originally vaguely sensitive 

 all over. 



With the development of the senses, the adjustments 

 between the organism and its environment gradually extend 

 in space, a multiplication of experiences and a correspond- 

 ing modification of conduct being the result. The adjust- 

 ments also extend in time, covering continually greater 

 intervals. Along with this extension in space and time 

 the adjustments also increase in speciality and complexity, 

 passing through the various grades of brute life, and pro- 

 longing themselves into the domain of reason. Very 

 striking are Mr. Spencer's remarks 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 

 intelligent 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 tactual range and 

 skill, and the consequent multiplication 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 tactuallip- 

 pendages go hand in hand. In the most intelligent an- 

 thropoid apes we find the tactual range and delicacy greatly 

 aligfnented, new avenues of knowledge being thus opened 

 to the animal. Man crowns the edifice here, not only in 

 virtue of his own manipulatory power, but through the 

 enormous extension of his range of experience, by the 

 invention of instruments of precision, which serve as sup- 

 plemental senses and supplemental limbs. The reciprocal 

 action of these is finely described and illustrated. That 

 chastened intellectual emotion to which I have referred in 

 connection with Mr. Darwin, is not absent in Mr. Spencer. 

 His illustrations possess at times exceeding vividness and 



