mouth and a digestive system, many of 

 them eyes, and some iiidiments of a nervous 

 one, implies a degree, more or less, of sensa- 

 tion in them all, and consequently that they 

 have all — whether it be molecular and dif- 

 fused in their substance, or confined to 

 particular organs — I say that they have all a 

 nervous influence and excitement sufficient 

 for their several wants, corresponding with 

 their several natures. 



These minim animals may be said almost 

 to be universally dispersed ; they inhabit the 

 sea, the rivers, and other waters ; are sup- 

 posed to float in the air ; they are found in 

 the blood and urine ; in the tartar of the 

 teeth ; in animal substances ; in vinegar ; 

 in paste ; in vegetable substances ; in fruits, 

 seeds, and grain ; in sand ; amongst tiles ; 

 in wells, on mountains, &c. Their numbers 

 are infinite ; hundreds of thousands may be 

 seen in a single drop of water ; their minute- 

 ness is extreme, some being not more than 

 one-two thousandth part of a line in length, 

 and yet these atoms of animals have a mouth 

 and several stomachs ! 



Let a man, says Dalyell, the translator of 

 Spallanzani, conceive himself in a moment 

 conveyed to a region where the properties, 

 and the figure and motions of every animal 

 are unknown. The amazing varieties of 

 these will first attract his attention. One is 

 a long slender line; another an eel or 

 serpent ; some are circular, elliptical, or tri- 

 angular ; one is a thin flat plate ; another 

 like a number of reticulated seeds ; several 

 have a long tail, almost invisible ; or their 

 posterior part is terminated by two robust 

 horns ; one is like a funnel ; another like a 

 bell, or cannot be referred to any object 

 familiar to our senses. Certain animalcules 

 can change their figure at pleasure : some- 

 times they are extended to immoderate 

 length, then almost contracted to nothing ; 

 sometimes they are curved like a leech, or 

 coiled like a snake ; sometimes they are in- 

 flated, at others flaccid ; some are opaque, 

 while others are scarcely visible from their 

 extreme transparence. No less singular is 

 the variety of their motions ; several swim 

 with the velocity of an arrow, so that the 

 eye can scarcely follow them ; others appear 

 to drag their body along with difficulty, and 

 move like the leech; and others seem to 

 exist in perpetual rest ; one will revolve on 

 its centre, or the anterior part of its head ; 

 others move by undulations, leaps, oscilla- 

 tions, or successive gyrations; — in short, 

 there is no kind of animal motion, or other 

 mode of progression, that is not practised 

 by animalcules. 



Their organs are equally various. Some 

 appear to take their food by absorption, 

 having no mouth; to this tribe belong what 

 have been called vinegar eels : others have a 



mouth and several stomachs, but no orifice 

 for the transmission of their excrements ; 

 others, again, have both a mouth and anal 

 passage, and what is wonderful, in such 

 minute creatures, sometimes as many as forty 

 or fifty stomachs : though many are without 

 eyes, others are furnished with these useful 

 organs, some having one, others two, others 

 three, and others four ; some have processes 

 resembling legs. In the second class of these 

 animals, the Eotatories, to which the wheel- 

 animalcules belong, the internal organisation 

 approaches to that of the higher classes, for 

 they exhibit the rudiments of a nervous 

 system ; their alimentary canal is simple ; 

 they have a branching dorsal vessel, but 

 without a systole and diastole ; their pharynx 

 is usually furnished with mandibles, which 

 are sometimes armed with teeth. The mouth 

 of the majority, especially amongst the rota- 

 tories, is fringed with ray-like bristles, 

 which Cuvier thinks are connected with their 

 respiration. This circumstance of a circle 

 of rays surrounding the oral orifice, is found 

 in the polypes and several other animals of a 

 higher grade. Their use in the present 

 instance, I speak more particularly of the 

 wheel-animalcules, is by their rotation to 

 produce a current in the water to the mouth 

 of the animal, bringing with it the still more 

 minute beings which constitute its food. 



Organisation so complex, and life, and 

 spontaneous motion, and appetite, and means 

 to satisfy it, and digestion, and nutrition, 

 and powers of reproduction in animals of 

 such infinite minuteness ! Who can believe 

 it? Yet so it is, and that each of these 

 should be varied in the different tribes and 

 genera ; that these less than the least of all 

 the creatures that present themselves to the 

 observation of mankind, and which till within 

 a century or two were not suspected to exist, 

 should out -number, beyond all statement of 

 numbers, all the other animals together that 

 people the whole globe ; that they should 

 probably enter into us and circulate in our 

 blood, nestle between our teeth, be busy 

 everywhere, and perceived nowhere, till the 

 invention of the microscope drew aside the 

 veil between us and these entities, and we 

 saw how God had filled all things with life, 

 and had based the animal k'ingdom upon 

 living atoms, as well as formed the earth and 

 the world of inert ones ! But to us, the 

 wondrous spectacle is seen and known only 

 in part ; for those that still escape all our 

 methods of assisting sight, and remain 

 members of the invisible world, may pro- 

 bably far exceed those that we know ! 



We may conclude that this vast, or rather 

 infinite host of animalcules, was not created 

 merely to be born and die ; was not sown, as 

 it were, over every part of the earth's surface, 

 lurking in seeds, and other vegetable and 



