[T]hat man should swim naturally, because we observe it is no lesson unto other animals, we cannot well conclude; for other animals swim in the same manner as they go, and need no other way of motion for natation in the water, then for progression upon the land. And this is true whether they move per latera, that is, two legs of one side together, which is Tollutation or ambling; or per diametrum, lifting one foot before, and the crossfoot behind, which is succussation or trotting; or whether per frontem or quadratum, as Scaliger terms it, upon a square base, the legs of both sides moving together, as Frogs and salient animals, which is properly called leaping. For by these motions they are able to support and impell themselves in the water, without alteration in the stroak of their legs, or position of their bodies.
But with man it is performed otherwise: for in regard of site he alters his naturall posture and swimeth prone, whereas he walketh erect. Again, in progression the arms move parallell to the legs, and the arms and legs unto each other, but in natation they intersect and make all sorts of Angles. And lastly, in progressive motion, the arms and legs do move successively, but in natation both together, all which aptly to peform, and so as to support and advance the body, is a point of Art, and such as some in their young and docile years could never attain. But although it be acquired by art, yet is there somewhat more of nature in it then we observe in other habits, nor will it strictly fall under that definition, for once obtained, it is not to be removed; nor is there any who from disuse ever yet forget it.
Sir Thomas Browne, Pseudodoxia Epidemica, London, 1658.
Illustration from J. Frost, Scientific Swimming; being a Series of Practical Instructions, on an Original and Progressive Plan, by which the Art of Swimming May Be readily Attained, with every Advantage of Power in the Water, London, 1816.
(Saturday Sports, #1)