Nor would I give way to him.  But I ceased switching, drew back a step, and looked at him with more respect than I ever before showed a snake.

The curved neck straightened at that, the glinting head swayed forward, and shivering through me as the swish of a stick never shivered through a snake, sounded that unearthly hissing whistle.  For a second—­for just the fraction of a second that it takes to jump—­I was, not scared, but shocked; and I slipped on something underfoot.  In three directions I wallowed the ferns before I got to my feet to watch the snake again, and by that time the snake was gone.

I found myself somewhat muddy and breathing a little hard; but I was not wholly chagrined.  I had heard and seen a black-snake whistle.  I had never even known of the habit before.

Since then I have seen one other snake do it, and I think I have heard the sound three or four times.  It is almost indescribable.  The jaws were closed as it was made, not even the throat moving, that I could see.  The air seemed to be blown violently through the nostrils, though sounding as if driven through the teeth—­a shrilling hiss, fine and piercing, which one not so much hears as feels, crisping cold along his nerves.

It may seem strange, but I believe this whistle is a mating-call.  Even the forked tongue (or maybe the nose) of a snake grows vocal with love.  If only the Sphinx had not possessed a heart of stone!  No matter about its lips; with a heart to know the “spring running” we should have heard its story long ago.  Perhaps, after all, the college sophomore was not mixing his observations and Sunday-school memories when he wrote, describing the dawn of a spring morning (I quote from his essay):  “Beneath in the water the little fishes darted about the boat; above the little birds twittered in the branches; while off on a sunny log in the pond the soft, sibilant croak of the mud-turtle was heard on the shore.”  If we could happen upon the mud-turtle mad with love, I am sure we should find that he had a voice—­a “soft, sibilant croak,” who knows?

I had long known the tradition among the farmers of the black-snake’s trailing its mate, following her by scent through grass and brush, persistent and sure as a sleuth-hound, until at last she is won.  I had been told of this by eyewitnesses over and over, but I had always put it down as a snake story, for these same witnesses would also tell me the hoop-snake story, only it was their grandfathers, always, who had seen this creature take its tail in its mouth and roll, and hit and kill a fifty-dollar apple-tree (the tree was invariably worth fifty dollars).  I had small faith in the trailing tale.

One day, the summer after my encounter in the ferns, I was sitting upon a harrow at the edge of the gravelly field that slopes to the swale, when a large black-snake glided swiftly across the lane and disappeared in the grass beyond.  It had been gone perhaps a minute, when I heard another stir behind me, and turning, saw high above the weeds and dewberry-vines the neck and head of a second black-snake.