Temple of Nature

Page 98

Additional Notes. for many successive years, till at length they acquire sexual organs or flowers. · 1 . A t h1. r d pre.J m]"t ce ag ainst the existence of spont.a neous vita p. ro-d uctw· ns h as b een the supposed want of analogy; this h. as also a.n sen from t h e expec t a tw. n, that the la' r(oJ 'er or m.o re com. plicated ammals should be thus produced; which have acqmred then pre~ent ~erfcc-t . b ccessive o·enerations during an uncounted senes of ages. 1011 Add toy sthui s, that th0 e want of analogy opposes the crec1 ·1 ·1· f 11 1 )1 tty .o . a llCW Cl I.S COVen· es , as of the magnetic needle, and coated clcctnc Jar, and Galvanic pile; which should therefore certait~ly ~e well weighed and nicely investigated before distinct cr~dence IS given them; but then the want of analogy must at length ytelcl to repeated ocular de­monstration. Prelimiumy obserlfJations. II. Concerning the spontaneous production of the smallest micro­scopic animals it should be first observed, that the power of_ reproduc­tion distinguishes oro-anic beinO', whether vegetable or ammal, from b b .. inanimate nature. The circulation of fluids in vessels may exist 111 hydraulic machines, but the power of T~prod~ction bclo~gs alon~ to life. This reproduction of plants and of anunals IS of two kmds, wluch may be termed solitary and sexual. The former of these, as in the r epro­duction of the buds of trees, and of the bulbs of tulips, and of the polypus, and aphis, appears to be the first or most simple mode of generation, as many of these organic beings afterwards acquire sexual organs, as the flowers of seedling trees, and of seedling tulips, and the autumnal progeny of the aphis. See Phytologia. Secondly, it should be observed, that by reproduction organic beings are gradually enlarged and improved; which may perhaps more rapidly and uniformly occur in the simplest modes of animated being; but occasionally also in the more complicated and perfect kinds. Thus the buds of a seedling tree, or the bulbs of seedling tulips, become larger and stronger in the second year than the first, antl thus improve till they acquire flowers or sexes; and the aphis, I Spontaneous Vitality of Microscopic Animals. believe, increases in bulk to the eighth or ninth generation, and then produces a sexual progeny. lienee the existence of spontaneous vitality is only to be expected to be found in the simpl~st modes of animation, as the complex ones have been formed by many successive reproductious. EJ1Jerirnental facts. III. By the ex periments of Buff'on, Reaumur, Ellis, Ingenhouz, and others, microscopic animals are produced in three or four days, according to the warmth of the season, in the infusions of all vegetable or animal matter. One or more of these gentlemen put some boiling veal broth into a pl1ial prevjously heated in the fire, and scaling it up hermetically or with melted wax, observed it to be replete with ani­malcules in three or four days. These microscopic animals are believed to possess a power of generating others like themsclve by solitary reproduction without sex; and these gradually enlarging and improving for innumerable successive generations. Mr. Ellis in Phil. Transact. V. LIX. gives drawings of six kinds of animalcula infusoria, which increase hy divid­ing across the middle into two distinct animals. Thus in paste com­posed of flour and water, which has been suffered to become acescent, the animalcules called eels, vibrio anguillula, are seen in great abund­ance; their motions are rapid and strong; they are viviparous, and produce at intervals a numerous progeny: animals similar to these are also found in vinegar; Naturalist's Miscellany by Shaw and N odder, Vol. II. These eels were probably at first as minute as other micro­scopic animalcules; but by frequent, perhaps hourly r eproclur,tion, have gradually become the large animals above described, possessing wonderful strength and activity. To suppose the eggs of the former microscopic animals to float in the atmo pherc, and pass through the sealed glass phial, is so contrary to apparent nature, as to be totally incredible! and as the latter are viviparou , it is equally absurd to suppose, that their parents float universally in the atmosphere to lay their young in paste or vinegar!