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Show 94 PARTICULAR CONSIDERATIONS ON THE quantity of water is very small, and the organic matte1 abundant, the production is usually of a vegetable nature~ ·when there is much 'vater, animalcules are more frequent· ly produced." It has been shown by the opponents of this theory, that when a vegetable infusion is debarred from the contact of the atmosphere, by being closely seal~ ed up or covered with a layer of oil, no ani1nalcules are produced; but it has 1>een said, on the other hand, that the exclusion of the air Inay ptevent some simple condjtion necessary for the aboriginal development of life-and nothing is more likely. Perhaps the prevailing doctrine is in nothing placed in greater difficulties than it is with regard to the entozoa, or creatures which live within the bodies of others. These creatures do, and apparently can. live '10Where else than in the iuterior of other living bodies, where they generally take up their abode in the vis. cera, but also sometimes in the chambers of the eye, the interior of the brain, the serous sacs, and other places having no communication from without. Some are vivip: wous, others oviparous. Of the latter jt cannot reasonably be supposed that the ova ever pass through the medium of the air, or through the blood-vessels, for they are too heavy for the one transit, and t0o large for the othet·. Of the former, it cannot be conceived how they pass into young animals-certainly not by communication from the parent, for it has often been found that entozoa do not ap~ pear in certain generations, and some of peculiar and noted character have only appeared at rare intervals, and in very extraordinary ci,·cumstances. A candid view of the }eds popular doctrine, as to the origin of this humble form of life, is taken 0y a distinguished living naturalist. "To explain the beginning of these worms within the human body, on the common doctrine that all created beings proceed from their likes, or a primordial egg, is so difficult, that. the rnoderns have been driven to speculate, as our fathers did, on their pontaneous birth; but they have received the hypothesis with some modification. Thus it i~ not from putrefaction or fermentation that the entozoa are born, for both of these processes are rather fatal to their existence, but from the aggregation and fit apposition of matter which is nlready organized, or has been thrown from organized surfaces. * * Their origi1 in this manner is not more wonderful or more inexplicable than that of many of the inferior animals from sections of • ORIGIN OF TH~ ANIMATED TRIBES. themselves. * * Particles of matter fitted by digestion, f\ll1i their transmission through a living body for immediate <1ssimilation \vith it, or flakes of lymph detached from 'iurfarcs already organized, seem neither to exceed no.r fall ':>Plow that simplicity of structure which favors this WOllJerful development; and the supposition that, like morsels of a planaria, they may als0, when retained in contact with living parts, and in other favorable circumstances, continue to live and be gradually changed into c.reatures of analogous conformation, is surely not so absurd as to be brought into comparison with the Metamorphoses of Ovid. * *' vVe think the hypothesis is also supported in some degree by the fact, that the origin of the entozoa is favored by all causes which tend to disturb the equality between the secerning and absorbent syst~ ms."* I-Iere particles of organized matter are suggested as the germinal origin of distinct and fully organized animals, many of \vhich have a highly developed reproductive system. How near such particles must be to the inorganic form of matter may be judged from what has been said within the last few pages. If, then, this view of the production of entozoa be received, it must be held as in no small degree favorable to the general doctrine of an organic creation by law. There is another series of facts, akin to the above, and which deserves not less attention. The pig, in its domestic state, is subject to the attacks of a hydatid, from which the wild animal is free; hence the disease called measles in pork. The domestic.ati on of the pig is of course an event subsequent to the origin of man ; indeed, comparatively speaking a recent event. Whence, then, the first progenitor of this hydatid? So al8o there is a tinea which attacks dressed wool, but never touches it in its unwashed state. A particular insect disdains all food but chocolatt>, and the larva of the oinopota cellaris lives now here but in wine and beer, all of these being articles manufactured by man. There is likewise a creature called the pynMlotles cycloJJ'um, which is only found in subterranean cavities connecled with certain specimens of the volcanic forn1ation in South America, dating from a time posterior to the arrangements of the earth for our species. Whence the first pymelodes cyclopum ·? vVill it, to a geologist, appear inational to suppo~e that, just a~ the plcrodactyle "' Articl~ ''Zoophytes," Bncycloptcdia Britanuica, 7th edition. ~ •~j |