22 THE FOUNDATIONS OF ZOOLOGY 



" Conscience, the last acquired faculty," says Maudsley, " is the 

 first to suffer when disease invades the mental organization. One 

 of the first symptoms of insanity — one which declares itself before 

 there is any intellectual derangement, before the person's friends 

 suspect even that he is becoming insane — is a deadening or com- 

 plete perversion of the moral sense. In extreme cases it is observed 

 that the modest man becomes presumptuous and exacting, the chaste 

 man lewd and obscene, the honest man a thief, and the truthful man 

 an unblushing liar. Short of this, however, there is an observable 

 impairment of the finer moral feelings — a something different, 

 which the nearest friends do not fail to feel, although they cannot 

 always describe it. Now these signs of moral perversion are really 

 the first symptoms of a mental derangement which may, in its 

 further course, go through all the degrees of intellectual disorder, 

 and end in destruction of mind, with visible destruction of the nerve- 

 cells which minister to mind. Is the end, then, dependent upon 

 organization, and is the beginning not ? " 



"Note, again, the effect which a severe attack of insanity some- 

 times produces upon the moral nature of the individual. The per- 

 son entirely recovers his reason ; his intellectual faculties are as acute 

 as ever, but his moral character is changed ; he is no longer the 

 moral man that he was ; the shock has destroyed the finest part of 

 his organization. Henceforth his life may be as different from his 

 former life as, in an opposite direction, was the life of Saul of Tarsus 

 from the life of Paul the Apostle to the Gentiles. An attack of 

 epilepsy has produced the same effects, effacing the moral sense as 

 it effaces the memory sometimes, and one of the most striking phe- 

 nomena observed in asylums is the extreme change in the moral 

 character in the epileptic which precedes and heralds the approach 

 of his fits. A fever or an injury to the head has, in like manner, 

 transformed the moral character." 



Passing this subject by for the present, it is clear that, consciously 

 or unconsciously, arbitrarily or naturally, freely or of necessity, every 

 living thing responds to some part of the order of nature, and that 

 the study of this order is part of biology ; for there are many 

 reasons, besides those we have considered, why the biologist should 

 have peculiar interest in the principles of science. His studies bring 

 him into intimate contact with certain conceptions which play such a 



