Fer-de-lance

As any herpetologist will tell you, the fer-de-lance is among the most dreaded snakes known to man.  When someone makes a present of one to Nero Wolfe, Archie Goodwin knows he's getting dreadully close to solving the devilishly clever murders of an immigrant and a college president.  As for Wolfe, he's playing snake charmer in a case with more twists than an anaconda -- whistling a seductive tune he hopes will catch a killer who's still got poison in his heart.