Some attain to seven feet in length; Holbrooke mentions one of nine feet, and ‘as thick as your arm,’ in common parlance. An angry snake of this size could, of course, blow with considerable force, and the term ‘bellowing’ might not unreasonably be applied to the sound; as it is also applied to the croaking of the ‘bull frog’ (_Rana mugiens_), the sound of which is really so like the lowing of cattle, that, on hearing one for the first time in the woods of Virginia, I looked round, quite expecting to see a young heifer in close proximity.[44] Probably, had the bovine lungs sounded at the same moment, the reptilian ‘bellow’ would have proved but a feeble imitation. A sound out of place, so to speak, or unanticipated, strikes upon the ear more forcibly than when expected. But if one reptile, and that a very small one, can so well imitate a bull as it is universally known the bull frog does, why may not another do the same?—an argument which I venture to use notwithstanding many herpetologists accept doubtfully the possibility of a snake producing such a sound. ‘Il est difficile à concevoir comment les serpents auraient la faculté de siffler, comme on pretend que peuvent le faire certaines espèces de couleuvres, et comme les poëtes se plaisent à nous les representer. Jamais nous n’avons pu entendre qu’un soufflement très sourd, provenant de l’air qui sortait avec plus ou moins de rapidité de l’interieur de leur poumon que l’on voyait s’affaisser en trouvant une issue par la glotte, à travers les trous des narines ou directement par la bouche dont la mâchoire superieure est naturellement echanchrée. Alors la bruit était seulement comparable à celui qui resulterait du passage rapide et continue de l’air dans un tube ou par un tuyau sec et etroit, comme serait celui d’une plume.’[45]