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120 SPONTANEOUS GENERATION.subsequent publications, declared that infusorial animalcules were directlyand spontaneously engendered from more highly organized bodies in a stateof putrefaction. This bold declaration was entirely approved by Buffon,who further maintained that with respect to these organisms such a modeof generation was not only the most frequent and universal, but also in allprobability the most ancient.Such being the definite position taken up by the advocates of spontaneousgeneration,it was not long before it was vigorously assailed, thecontroversy that ensued surpassing probably in acrimony and the extentof its duration that of any yet brought within the area of scientific polemics.The earliest authority to declare himself opposed to this doctrine and tosubmit an intelligible interpretation of the apparently anomalous conditionsof growth and reproduction of infusorial organisms, is usually held to bethe Abbe Lazzaro Spallanzani, of Pavia, who in the year 1765 enunciatedthe opinion that such animalcules were propagated through themedium of minute germs constantly present in the atmosphere, andwhich fructified or developed immediately they came in contact withthe conditions suitable for their growth furnished by artificial or otherinfusions. The atmospheric "germ theory," attributed to Spallanzani, canboast, however, of a far more remote antiquity. Seventy years prior tothe time of Spallanzani (1696), an Englishman, John Harris, whose nameas one of the earliest observers of infusorial life has been previouslyquoted, contributed to the ' Philosophical Transactions ' a suggestion concerningthe generation of these minute beings that is now, almost twocenturies later, found to represent the true position of the case more nearlythan any of the manifold interpretations brought forward between that dateand the present time. In the course of his observations upon the subjectof infusorial animalcules, embodied in the foregoing communication, thefollowing paragraph occurs :"How such vast numbers of animals can be as it were at pleasure, produced,without having recourse to equivocal generation, seems a very great difficulty toaccount for. But the solving of it that way makes short work of the matter (for'tis easie enough to say they are bred there by putrefaction), yet the assertingequivocal generation seems to me to imply more absurdities and difficulties thanperhaps may appear at first sight, i wish therefore that this matter would a whileimploy the thought of some ingenious and inquisitive man. In the mean time I'veconjectured that these animalcula may be produced by one or both of the followingways.I. I have thought that the eggs of some exceeding small insects, which arevery numerous, may have been laid or lodged in the plica? or rugae of the coats ofthe grain by some kinds that inhabit the same as their proper places. For thatinsects of the larger kinds do frequently thus deposite their eggs on the flowers andleaves of plants, has been often experimented and 'tis ;very probable that the smalleror microscopical insects do the same. Now these being washed out of the seeds, bytheir immersion in water, may rise to the surface and there be hatched into thoseanimals which we see so plentifully to abound there. II. Or the surface of thewater may arrest the straggling eggs of some microscopical insects that were perhapsabout in the air, and being fitted and prepared for the purpose, by the infusion ofproper grain, or a proportionable degree of heat, may compose so proper a nidus