294 ANNUAL OF SCIENTIFIC DISCOVERY. 



to make the possession of a stomach a distnietive feature of animal 

 nature is shown by the history of a group of creatures, of whicli tiie 

 well-known and common amaj!)a may be taken as a type. In 

 these, tiiere can be no question of dctinition ; for in no sense what- 

 ever ean they lie said to possess a permanent stomach. 



*'Tlie ama3ba has a just claim to the title of animal, for its 

 affinities with the foraminifera are clear; and no one would deny 

 that tliese creatures, with their exquisitely bcautiiul shells, are 

 animals. Yt't the amoeba has no stomach, — possesses, indeed, no 

 organs at all, unless we consider its so-called nucleus as one ; and 

 there are closel}' allied forms in which even this is absent. Con- 

 ceive of a minute drop of transparent jelly, so small as to be in- 

 visible without the help of a microscope, — a drop of jelly sj)rink]ed 

 and studded with a dust of opacpie granules, sometimes hiding in 

 its midst a more solid rounded body, or kernel, called the nucleus, 

 and perhajjs with the outer rind a little difterent from the internal 

 mass. Conceive, further, of this amoeba as of no constant shape, 

 but, like the Empusa, siiiiling, as we look upon it, from one form 

 into another. At one moment, it is like a star with straggling, 

 unequal limbs; at another, club-sha])ed : now it is a rounded 

 square; soon it will be the image of an hour-glass. None of 

 these changes can be referred to currents in the water in which 

 it lives, or to any other forces acting directly upon it from wiili- 

 out. It seems to have within it some inner spring, an inl)orn 

 power of flowing, whereby this part of it or that moves in this or 

 that direction. And not only do its parts thus shift and change 

 in form, but through their changes the whole body moves from 

 place to place. As we begin to watch it, for instance, at the 

 moment when it is in what may be called its rounded phase, a 

 little protuberance mat be seen starting out on one side. Sj)eed- 

 ily the little knob swells, lengthens, flows into a long process. 

 The process thickens, faint streams of granules indicating in wliich 

 way the currents of the unseen molecules are setting. The sub- 

 stance of the body surges into the process ; and as the latter widens 

 and grows thick, the former shrinks and grows small. At last the 

 whole body has flowed into the process; where the body was, 

 there is now nothing, and where the process reached to, the whole 

 bod^' now is. The creature lias moved, has flowed from one spot 

 into another. Here, then, we have movement without muscles, 

 locomotion without any special organs of locomotion. We have, 

 also, feeling without nerves or organs of sense ; for if a process 

 such as we have described, while flowing out, meet with any ob- 

 noxious body, it will shrink back, and stop in its work. And the 

 whole body, terrified by some potent shock, will often gather 

 itself up into a ball. As it moves without muscles, so, also, does 

 it eat without a st(»mach. Meeting, in its sluggish travels, with 

 some morsel (and diatoms are its frequent food), it pours itself 

 over its meal, and, coalescing at all points around it, thus swallows 

 its food by fluxion. To use a homely illustration, it is much as if 

 a piece of living mobile dough were to creep ground an apple, 

 and to knead itself together into a continuous envelope, in order to 

 form an apple-dumpling. Watching the food thus enveloped by 



