Be Thou Wary of the Bubbling Cup
A PROFESSOR in a western university has discovered that small organisms lodge in a great many kinds of bubbling-cup drinking fountains, and for a curious reason based on an ancient physical principle.
Twenty-five years ago writers of textbooks on physics had not the wealth of material to draw from that is now available. In carrying out one of their few experiments a rubber-tube-andspout arrangement was prepared in such a way that it could be attached to an ordinary water faucet and a small jet of water was projected directly upward. In this jet a small ball would be placed— and, curiously enough, would remain in the air, almost stationary, held up by the jet. The jet seemed to clutch the ball and hang onto it instead of throwing it away. The stream would divide under the ball, come up equally on all sides and hold it in place. The sphere might oscillate up and down slightly, but otherwise it appeared to be settled permanently in place.
The western professor mentioned has discovered that bacilli may oscillate up and down in some kinds of bubbling cups all day long, day after day—in the same way and for the same reason that the sphere did in the old-time jet.