Note 119 — CHAP. VIII. OF THE ANIMALCULA INFUSORIA.

Chambers’s Cyclopedia by Rees, Art. Animalcule.

[120] Minute animals proportionably exceed the larger kinds in strength, activity, and vivacity. It has been already observed, p. 212, that the spring of a flea vastly outstrips any thing animals of a greater magnitude are capable of; the motion of a mite is much quicker than that of the swiftest race-horse. M. De L’Isle, Hist. Acad. Scienc. 1711. p. 23, has given the computation of the velocity of a little creature, so small as to be scarcely visible, which he found to run three inches in a second; supposing now its feet to be the fifteenth part of a line, it must make five-hundred steps in the space of three inches, that is, it must shift its legs five-hundred times in a second, or in the time of the ordinary pulsation of an artery. The rapidity with which many of the water insects skim the surface of the fluid, and others swim in it, is astonishing, nor is the celerity of the various species of animalcula infusoria less deserving of admiration. Edit.