The Jump of a Flea.

M. de Fonvielle, in his interesting work on the "Invisible World," maintains that a flea can raise itself from the ground to a height equal to two hundred times its stature. At this rate, he says, a man would only make a joke of jumping over the towers of Notre-Dame or the heights of Montmartre. A prison yard would be useless unless the walls were more than a quarter of a mile in height.