risibility

"Bushido" Chapter XI, SELF-CONTROLの一節です。
Indeed, the Japanese have recourse to risibility whenever the frailties of human nature are put to severest test. I think we possess a better reason than Democritus himself for our Abderian tendency; for laughter with us oftenest veils an effort to regain balance of temper, when disturbed by any untoward circumstance. It is a counterpoise of sorrow or rage.
この "risibility" は直ぐに憶えて置きたい単語です。　辞書の説明を見ます。
・Merriam-Webster's Online Dictionary:
　1 : laughter
　2 : the ability or inclination to laugh -- often used in plural (our risibilities support us as we skim over the surface of a deep issue -- J. A. Pike)
・Webster's Revised Unabridged, 1913 Edition
The quality of being risible; as, risibility is peculiar to the human species.
・Webster's New World College Dictionary:
1. the quality or state of being risible; ability or inclination to laugh
2. a sense of the ridiculous or amusing; appreciation of what is laughable
Wordnikは例文が豊富な辞書で、そこから例文を一つ引用します。
No one enjoys a joke better than an Esquimaux, and when his risibility is excited he laughs with right good will, evincing in this, as in every other respect, the difference of disposition between them and the Indians, whose rigid features seldom betray their feelings.
上の辞書にも "risibility" は人間に特有の能力と説明がありますが、動物でも嬉しそうな表情を見せる時があるのであながち人間だけの能力でも無い様な気がします。