William now evinces a disposition to find fault with his home, his clothing, his food, and restrictions on his conduct and routine. He betrays a mental uneasiness unknown to prepubertal days, and a willingness to argue with his parents in a self-assertive or combative mood quite unlike his former self. Incongruities of character are shown in petulance, irritability, disobedience, stubbornness, and rebellion, sometimes even taking the form of cruelty to persons or animals. This latter manifestation has been ascribed to atavism which manifests itself in the recurrence of the savage traits of his primeval ancestors. Dr. G. Stanley Hall thus comments on this tendency in his exhaustive work on adolescence: “Assuming the bionomic law, infant growth means being loaded with paleoatavistic qualities in a manner more conformable to Weismannism, embryonic growth being yet purer, while the pubescent increment is relatively neoatavistic.” His proximity to the savage state is shown in his appreciation of primitive humor. The unexpected which causes discomfiture or pain is excruciatingly ludicrous. It is the crude, slap-stick comedy which excites his disposition to risibility. The knockabout comedian who falls down stairs or beats his partner over the head with an inflated bladder produces the same degree of laughter in a boy as the felling of one savage by another with a war club produces in the onlooking members of their tribe. The rapier wit of keen intellectuality and the subtle humor of fine distinctions observed in a play on words all pass over his unscathed head. He is a living paradox who displays at times the gallantry, courtesy and chivalry of the knight-errant with the thoughtlessness, rudeness, and boisterousness of the harum-scarum rowdy.