Используйте «sibilation» в предложении

1. Several persons pursuing a pathway, passed within a few inches of one of them without his betraying any emotion, but the moment he perceived me advancing with my eye fixed upon him, he with a sudden exertion assumed a defensive attitude, by elevating the anterior portion of his body, flattening his head, and 3 or 4 inches length of his neck; these he waved with a steady and oblique motion from side to side, uttering at the same time an audible sibilation, he made no attempt to escape, and seemed absolutely fearless until taken