VERMES. 



apparatufes : there are, in a few, barely digeftive vifcera, 

 and fome indications of refpiration. They have no circula- 

 tion, no nerves, no centre of fenfation : each part of the 

 body feems to imbibe immediately the materials of its nu- 

 trition, and to poffefs, within itfelf, the power of fenfation. 



Hence moft of thefe animals have very ftrong reproduftive 

 powers, quickly reiloring injured or loft parts. Some of 

 them indeed are multiplied by a fimple divifion, bke plants. 

 There are however different degrees in this fimplicity, which 

 is common to all. We pafs fucceffively from beings, which 

 have feet, tentacula, hard and foft parts, and diftincl vifcera 

 {viz. the Echino-dermata), to others, whofe whole body is a 

 gelatinous mafs varioufly (haped (Meduf^s), or, when ex- 

 amined with the moft powerful microfcope, prefents an ap- 

 parently indivifible atom (Infuforia). 



Stagnant water, infufions of vegetable fubftances, the 

 recent feminal fluids of animals, &c. teem with animated 

 points, round, oval, or of other fip\ires, with or without a 

 fmall appendix forming a tail, only vifible, for the moft 

 part, by means of ftrong magnifying powers. 



In the arrangement of LamarcK thefe creatures form 

 a diftinft clafs, with the name Infuforia. As they are 

 merely microfcopic objefts, we can only fay of them, that 

 they are minute, gelatinous, femitranfparent points, in fome 

 of which more opaque fpots are vifible, homogeneous, irri- 

 table throughout, and contrading in every direftion ; con- 

 fequently changing their form frequently, but generally 

 affuming, when at reft, a determinate figure in each fpe- 

 cies. We confider that thefe little bodies, which are mere 

 animated points, and conftitute, if we may ufe fuch an ex- 

 preffion, the ultimate term of organization (ultimate at leaft 

 to our means of refearch), are nouriftied byabforption from 

 their whole furface, and are probably excited by the fur- 

 rounding influences of caloric, electricity. Sec. Thus they 

 refemble vegetables, which live by abforption, executing no 

 digeftion, and performing organic motions in confequence of 

 external excitation. But the infuforia are irritable and con- 

 traftile, and execute fudden motions, which they can repeat : 

 this charafterizes their animal nature. 



The genus Monas of Cuvier, or Chaos of Blumenbach, 

 includes the fimpleft known animals. The latter author di- 

 vides his Chaos into aquatile, infuforium, and fpermaticum, 

 according as the animals are found in water, in vegetable 

 infufions, or in animal femen. For a defcription of the latter, 

 we refer to the article Generation ; fome of the former 

 are noticed under Animalcule. The Volvox is a round, 

 yellowifti or greenifh, gelatinous, and nearly tranfparent ani- 

 malcule, which fwims round and round, and moves about 

 without any vifible organs of motion. It (volvox globator) 

 abounds in fummer in the water of marlhes, and then has a 

 reddifti colour. In its interior we can diftinguifh globes 

 fimilar to itfelf, which come out of its body, move about in 

 the fame way, and are feen to contain other fmaller ones ; 

 fo that the animal may be faid to be pregnant at once with 

 feveral fucceffive generations. The volvox conflitlor is found 

 ' in the water of dunghills, and moves by turning alternately 

 to the right and left. It contains internally round mole- 

 cules, which move about alfo. 



The appearance of thefe animalcules, their motions, and 

 the multiplication of fome fpecies, lead us to afcribe them 

 to the animal kingdom ; but doubts are entertained on the 

 fubjeft. In that fenfe, at leaft, we underftand the remark 

 of Cuvier, " On feroit nieme teniedecroire que plufieurs de 

 ces aniniaux microfcopiques ne fe ferment que de la decom- 

 pofition des mati^res foumifesa I'infufion." Tab. Element. 

 p. 663. 



They who believe them to be animals, are again divided 



in opinion refpefting the mode of their produftion ; fome 

 arguing from analogy that they are produced by generation 

 of fome kind, while others admit of a fpontaneous origin, or 

 what has been commonly called equivocal generation. Spal- 

 lanzani made feveral experiments to determine this point. 

 Long boiling accelerated the produdion of the animalcules ; 

 which were alfo produced from the infufion of vegetable 

 feeds burnt with the blowpipe. When boihng infufions were 

 put into glals tubes, and thefe immediately hermetically 

 fealed, no animalcules were produced. Eleftiicity, tobacco- 

 fmoke, oleaginous, fpirituous, and corrofive liquors deftroy 

 them. They will live a month in vacuo ; but are not pro- 

 duced in that fituation. Spallanzani's Trafts on Animals 

 and Vegetables. 



Refpefting this doftrine of equivocal generation, we may 

 obferve, that the only argument in its favour is the indireft 

 and unfatisfaftory one arifing from its oppofers being unable 

 to (hew that the creatures in queftion are produced by a 

 procefs of generation. The analogy of all nature, down to 

 the minuteft infedls, which our microfcopes enable us to in- 

 veftigate, affords a very ftrong prefumptive proof againft it, 

 and leads us to conclude, that if our means of examination 

 were more perfeft, we ftiould find that thefe creatures are 

 produced and multiplied like all other animated beings. 



There are numerous other fpecies named after differences 

 of form, or according to the circumftances under which 

 they are produced. The Proteus has the fingular property 

 of changing its form, almoft incefiantly, into every poffible 

 modification of figure. The fmall animals found in vinegar 

 and palle (Vibrio aceti et glutinis), generally called eels from 

 their elongated figure, are almoft large enough to be diftin- 

 guiflied by the naked eye. Freezing does not deftroy 

 them ; but evaporation does, unlefs they are protefted by 

 a little duft from the contaft of the air. It is faid that 

 they change their llvin, that they have different fexes, and 

 produce young ones alive in fpring, then lay eggs till 

 autumn. 



The genera juft enumerated, viz. Monas, Volvox, Pro- 

 teus, Vibrio, together with two other?, Burfaria and Kol- 

 poda, make up the ord'.-r infuforia nuda of Lamarck ; that 

 is, fuch as have no external appendices. He has a fecond 

 order of infuforia appendiculata, including fuch infufion 

 animalriiles as exhibit any prominent part like hairs or tail, 

 &c. The feminal vermiculi, as they have been termed, 

 (cercarix, Lamarck,) belong to this order, for they have 

 a tail. 



It includes alfo the genus or family of the tricho-cercK 

 and trichodce. 



We come next to animalcules a little more complicated 

 in their ftrufture : they poffefs ftellated organs, confifting of 

 fine ciliated proceffes lurrounding an opening, and fufcep- 

 tiblc of motion, with the fuppofed objeft of drawing their 

 prey towards the aperture. 



The following anitnals are formed by Lamarck into an 

 order which he calls Polypi, and which we deem a very 

 natural one. They are gemmiparous, or multiply by 

 ftioots. They have a fmall elongated body, homogeneous, 

 gelatinous, very irritable, poffefling wonderful reproduftive 

 powers, provided at its upper end with a mouth, which is 

 furrounded by rotatory organs, or radiated tentacula, and 

 ferves as the entrance of an ahmentary cavity which has 

 no other opening. This cavity is the only organ they pof- 

 fefs ; it is ufually an elongated bag, feldom folded on itfelf, 

 or poffefling any appendages. Such is the idea of a polype : 

 when feveral of thefe little bodies are connefled together, 

 and participate a common life, they compofe the animals of 

 zoophytes. 



The 



