Department of History
University of California, Irvine
 Instructor:    Dr. Barbara J. Becker


Week 5.  Mechanism

excerpts from
"A Summary of Some Late Observations upon the Generation, Composition, and Decomposition of Animal and Vegetable Substances...." (1748)
by John Turbervill Needham (1713-1781)
from Philosophical Transactions, vol. 45:  615-666


Paris, Nov. 23, 1748, N.S.
[the date given is according to the "new style,"
or Gregorian Calendar, which was not
officially adopted in England until 1752]


THO' I think myself now almost sufficiently qualified, by the Multitude of Experiments I have already made upon animal and vegetable Substances, since the 16th, N.S. of last March, to lay down some certain Truths upon this Subject, and from them to advance, by Induction, farther than so short a Period of Time would allow me to proceed by special Experiments, yet I would have your learned Royal Society look upon this Paper as an imperfect Sketch only of what I hope to publish from the Journals I have by me in a few Months, if these two or three Sheets are so fortunate as to meet with their Approbation.  I am sufficiently sensible how much I may hurt this little Performance, if I promise too much, and raise in this Matter higher Expectations from the Public than it may appear hereafter to deserve:  It is at this time therefore particularly the more necessary, that I should be exceedingly cautious to advance no Proposition rashly; nothing, but what seems to flow naturally from Observation.  But this Precaution, however strict, will not exclude now-and-then a probable Consequence from appearing, provided it seems connected with some preceding manifest Truth; for such must be allow'd, as proper Foundations for a more exact Inquiry in a Matter I am very far from pretending to have exhausted.  I must therefore observe, for my own Security against future Objections, that tho' I add no new decisvie Experiment to my present List, or throw any more Light upon the Subject than what I have already amassed, I may possibly, before my Essay appears, whether by the Advice of Friends, or otherwise, conceive more mature Thoughts, reject some of the present, and adopt others in their Place.  As this will be done, without affecting in any degree the main System, which I imagine turns upon unquestionable Truths, it is a Liberty I am persuaded that equitable and learned Society will indulge me in, if no other Consideration prevails, than the great Obscurity that hangs over a Subject so extensive and so intricate as this is; in which I am already engag'd much farther than I at first foresaw, and indeed too far to recede without saying something....

§21.  For my Purpose therefore, I took a Quantity of Mutton-Gravy hot from the Fire, and shut it up in a Phial, clos'd up with a Cork so well masticated, that my Precautions amounted to as much as if I had sealed my Phial hermetically.  I thus effectually excluded the exterior Air, that it might not be said my moving Bodies drew their Origin from Insects, or Eggs floating in the Atmosphere.  I would not instil any Water, lest, without giving it as intense a Degree of Heat, it might be thought these Productions were convey'd through that Element.  Seeds or Plants were for this Reason improper, because they might have been judg'd to have been previously adhering to these Plants or Seeds:  I neglected no Precaution, even as far as to heat violently in hot Ashes the Body of the Phial; that if any thing existed, even in that little Portion of Air which filled up the Neck, it might be destroy'd, and lose its productive Faculty.  Nothing therefore could answer my Purpose of excluding every Objection, better than hot roast-Meat Gravy secur'd in this manner, and exposed for some Days to the Summer-Heat:  and as I was determined not to open it, till I might reasonbly conclude, whether, by its own Principles, it was productive of any thing, I allow'd sufficient Time for that Purpose to this pure unmix'd Quintessence, if I may so call it, of an animal Body.  From this time I take Corruption intirely in a philosophical Sense, for the rising of a dead Substance, by a new kind of Vegetation, into Life:  and no Axiom, how much soever it may have been exploded, is more true than that of the Antients, Corruptio unius est Generatio alterius; though they drew it from false Principles, and so established it as to render Generation equivocal, and never penetrated sufficiently into Nature by Microscopes, to discover this Class of Beings, that are neither generated nor generate in the common Way, yet furnish a Key to lead to the Generation of all others.  My Phial swarm'd with Life, and microscopical Animals of most Dimensions, from some of the largest I had ever seen, to some of the least.  The very first Drop I used, upon opening it, yielded me Multitudes perfectly form'd, animated, and spontaneous in all their Motions:  And thus was I obliged to abandon not only the Notion preconceiv'd of a Distinction to be made in this Class of Animals, between those that appeared under a sensible Angle in the Microscope, and the atomical ones; but even that Hypothesis also which I had advanc'd as probable, in the little Essay I published in 1745, that spermatic Animals were no more than Multitudes of such Machines as those of the Calamary; for now it was plain of what kind they were, and whence they deriv'd their Origin.

§22.  I shall not at this present time trouble you with a Detail of Observations upon three or four Scores of different infusions of animal and vegetable Substances, posterior to these upon Mutton-Gravy; all which constantly gave me the same Phænomena with little Variation, and were uniform in their general Result:  These may better appear at Length upon some other Occasion; let it suffice for the present to take notice, that the Phials, clos'd or not clos'd, the Water previously boil'd or not boil'd, the Infusions permitted to teem, and then plac'd upon hot Ashes to destroy their Productions, or proceeding in their Vegetation without Intermission, appear'd to be so nearly the same, that, after a little time, I neglected every Precaution of this kind, as plainly unnecessary.  I take no notice yet of their Manner of being generated and generating; in relating these Discoveries, as I believe I shall be more intelligible, if I follow the Order of Time:  It is a Justice moreover I owe both to Mr. de Buffon [French naturalist, Georges Louis Leclerc, Comte de Buffon (1707-1788)] and myself; for some were made by him alone, some by me, and some of them in Concert together:  His System, the Detail of his System, his Experiments, my own Discoveries, my Thoughts in consequence of these Discoveries; all these were reciprocally communicated; we made a Secret of nothing to each other.  Thus where one Truth seems to lead to, or is the natural Consequence of another, it will be easy, from the Order I have observ'd, to see how much I have been obliged to his Penetration and Foresight.  But this will yet appear more distinctly, when our several Essays upon this Subject shall appear; and in the second Volume of his Natural History, which will very soon be published, I must declare for a Fact, that all which precedes his Accounts of the Experiments, begun March 16. N.S. of this present Year 1748, was previous either to his own Experiments or mine, and was read to me by himself....

§26.  My first Proofs therefore were drawn from a close Attendance to all the common Inufsions, particularly that of Wheat pounded in a marble Mortar.  It was plain from them all, that after some time allow'd to the Water to call off the Salts and volatile Parts, which evaporated copiously, the Substance became softer, more divided, and more attenuated:  To the naked Eye, or to the Touch, it appear'd a gelatinous Matter, but in the Microscope was seen to consist of innumerable Filaments; and then it was that the Substance was in its highest Point of Exaltation, just breaking, as I may say, into Life.  These Filaments would swell from an interior Force so active, and so productive, that even before they resolved into, or shed any moving Globules, they were perfect Zoophytes teeming with Life, and Self-moving.


If any Particle was originally very small and spherical, as many among those of the pounded Seeds were, it was highly agreeable to observe its little Star-like Form with Rays diverging on all Sides, and every Ray moving with extreme Vivacity.  The Extremities likewise of this gelatinous Substance exhibited the same Appearances, active beyond Expression, bringing forth, and parting continually with, moving progressive Particles of various Forms, spherical, oval, oblong, and cylindrical, which advanced in all Directions spontaneously, and were the true microscopical Animals so often observed by Naturalists.  This brings to my Mind a Phænomenon often taken notice of, and seen with Surprize, Particles detach'd by the Reaction of the Water from the Extremities of the Fins of Mussels, which yet continue to move progressively.  I think it sufficiently explain'd by these Observations; and that it is more than probable, that Mussels, Polypes, and other Kinds of this Nature, vegetate in a Manner analagous to this gelatinous Matter.  See Fig. 2.

§27.  In the Infusion of pounded Wheat, the first Appearances, after an Exhalation of volatile Parts, as in every other Infusion, were the second or third Day Clouds of moving Atoms, which I suppose to have been produced by a prompt Vegetation of the smallest and almost insensible Parts, and which requir'd not so long a Time to digest as the more gross.  These in a Day or two more intirely disappeared; all was then quiet, and nothing to be seen, but dead irregularly formed Particles, absolutely unactive till about fourteen or fifteen Days after.  From these united into one Mass sprung Filaments, Zoophytes all, and swelling from a Force lodged within each Fibre.  These were in various States, just as this Force had happen'd to diversify them; some resembled Pearl-Necklaces, and were a kind of microscopical Coralloids; others were uniform throughout their whole Length, except just the very Extremity, which swell'd into a Head like a Reed, if the Force had acted equally on all Sides, or like the Head of a Bone at its Joint, if the Matter in its Expansion had bore to either Side.  These Filaments were all Zoophytes, so teeming with Life, that whenever, upon taking a Drop from the Surface of this Infusion, I had separated the Extremity of a Filament so short as not to consist of above four or five Globules Chaplet-wise; they would advance progressively and in Concert, with a sort of vermicular Motion, for a little Way, then fall off irregularly to one Side, as if not yet fitted for progressive Motion, languidly turn their Extremities, and then again lie quiet for some little time.  It was my Fortune however, not in this Infusion only, but in many others, to find some of these Chaplet-like Animals much smaller indeed than those of the Wheat-Infusion; but intirely regular, constant in their vermicular Motion, and which were consequently arrived to a higher Degree of Maturity and Perfection.  I own I cannot but wonder to this Day at what I saw; and tho' I have now seen them so often, I still look upon them with new Surprize.  Yet have these Phænomena serv'd me to very good purpose, and cleared up many Difficulties in my former Observations.

The Origin of Blight in Wheat, Rye, and other Vegetables, was no longer mysterious:  An Atmosphere charg'd to an extraordinary Degree with Humidity, now plainly appear'd sufficient, particularly while the Grains were tender and replete with a milky Juice in a certain Degree of Exaltation, to produce in them this new kind of Vegetation, and to form their interior Substance into Filaments, which are indeed those very Eels I observ'd some Years ago in blighted Wheat....

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