Fer-de-Lance by Rex Stout

The fer-de-lance is among the most deadly snakes known to man. When someone makes a present of one to Nero Wolfe, his partner, Archie Goodwin, suspects it means Wolfe is getting close to solving the devilishly clever murders of an immigrant and a college president. But this is a case with more twists than an angry rattler...and if Wolfe doesn’t handle it with extreme care, he’ll be the next one struck by a killer with poison in his heart.