cut it #2

古くは祭祀用メスの材料として使われたobsidian（黒曜岩）に関するCNNの記事から英語表現を拾います。見出しのcut itはすでにブログで採り上げられている表現ですが「十分である, 期待にこたえる」（『プログレッシブ英和中辞典』小学館）という意味の表現。またここでのcut itが黒曜岩の「切れ味」と掛けたものであることは言うまでもありませんね。（Koyamamoto）

cf. http://d.hatena.ne.jp/A30/20130228/1362063526

How Stone-Age blades are still cutting it in modern surgery
(CNN)Ever had a headache so big, you felt like drilling a hole in your head to let the pain out?
In Neolithic times trepanation -- or drilling a hole into the skull -- was thought to be a cure for everything from epilepsy to migraines.
It could even have been a form of emergency surgery for battle wounds.
But while there is still conjecture about the real reasons behind the mysterious procedure, what is known is that the implement often used to carry out the primitive surgery was made from one of the sharpest substances found in nature -- obsidian.
http://edition.cnn.com/2015/04/02/health/surgery-scalpels-obsidian/index.html