William Henry Dallinger

“ As to the development of bacteria in infusions charged with solid matter, precise experiment of a sufficiently comprehensive character has yet to be made on them, in relation to the demonstrated germs. Meantime, shall we accept "spontaneous generation" on such ground as its strongest advocate has now to offer, and ignore the vast chain of facts copiously attested and controlled, which are in perfect harmony with the known laws of the entire organic world? ”

“ It is to be regretted when, in a matter so purely one of rigid science as this is, impassioned controversy is suffered to have any place. It fails utterly of its intended purpose, and simply hinders and delays the final issue. ”

“ Bastian's position in relation to the origin of minute organic forms has, at the outset, the immense disadvantage of being adverse to the whole analogical teaching of Nature, down to the uttermost depths of minuteness, where our knowledge is accurate and sound. Wherever science has put down the landmarks of possession, and is not dealing with the disputable territory of hypothesis, it is absolutely known that at some period in the cycle of development the lowliest organisms are dependent for their propagation upon what we can only look upon as genetic products. ”

“ They decline to determine the exact manner or line of that continuity until they have facts of a competent kind to guide them. There may be lines of continuity infinitely more subtile than any the subtilest minds have even conceived. At least they decline to accept one, laid down, as it appears to them, not by Nature, but by Dr. Bastian; and no believer in the evolution of living things, surely, is recreant of his creed who declines a similar surrender.
The largest difficulty surrounding the question of the mode of origin of septic organisms is that of discovering their life-cycle. ”

“ I am equally convinced that the death-point of bacteria-germs hovers very near the boiling-point of water—a conviction amply sustained by fact. This being so, the survival, as germs, of some few, amid incalculable myriads, by some accidental protection, is surely possible. So that, indeed, all true work now should be a study of the germ and its properties, and a discovery by patient research of the life-history of the organism.
The valueless nature of mere temperature experiments on such organisms, as tests of their ability to survive, without a knowledge of their life-history, Dr. ”

“ Of the developmental history of these organisms themselves, we know from actual observation almost nothing with certainty; and the little we do know from such careful and patient observers as Cohn, Billroth, Ray, Lankester, and others, is so complex and conflicting as to demonstrate the necessity of years of patient experiment and skilled research, and to plainly tell us of our ignorance of this minute and wonderful group of organic forms. ”

“ Their minuteness, their capability of being physically demonstrated, the absolute necessity of their presence to the origination of bacteria in sterilized infusions of any and every kind, taken in connection with what we know concerning the germs of the heteromita whose life-histories have been studied, render it simply inevitable that we have at length reached, what we are justified in believing to be, a genetic product of the bacteria through which their continuation as organisms is preserved. ”

“ It must be hard, defiant fact, which none can gainsay. But verily no such facts—nor even their most distant forecasts—are before us. The profound difficulties which bristle round the inquiry on every hand are prominent signals for caution; while the uncertainty and incompetency of the methods hitherto employed, and their conflict of results, is alive with meaning. Indeed, we are dealing with organisms so minute as to elude all but our best optical appliances ”

“ Manifestly, then, it must be weighty—nay, unequivocal and even irresistible—evidence that will induce the philosophical biologist to conclude that Nature's otherwise universal method is changed, in the outmost fringe of organized being. ”

“ I have drawn from Nature, in the six respective cases, the condition presented by each organism at the time of emitting its spores. Fig. 1 is the genetic product of an oval monad, with a pair of flagella; it rapidly increased by fission; then in a remarkable manner a pair blended, became one in the form of a sac, the sac burst and poured out, as the drawing portrays, innumerable spores, which were watched continuously until they were seen to develop into the parent condition. Fig. 2 gives a similar product of another form ”

“ But at right angles to a luminous beam passing among these particles in the fluid "they discharge perfectly polarized light. . . . The optical deportment of the floating matter of the air proves it to be composed, in part, of particles of this excessively minute character," and it is among the finest of these ultra-microscopical particles that Prof. Tyndall finds the sources of bacterial life. It is almost impossible to conceive a nearer approach to certainty concerning the nature of these minute particles than this. ”

“ Nothing that has yet been alleged, by way of objection to the admission of spontaneous generation as an every-day fact, at all affects such experiments as these. The shortest way out of the difficulty would, therefore, be to doubt the facts. ”

“ But it has been shown that the monad has germs, and that these have a power of resisting heat up to 300 Fahr.—that is to say, 25 Fahr. higher than that to which Dr. Bastian's infusion was exposed—and therefore, by the logic of facts, the monads found were not a result of "spontaneous generation," but were the natural outcome of a genetic product contained in the infusion, and which the heat employed could not destroy.
We need no stronger proof of the futility of reasoning concerning the thermal death-point of a minute organism where developmental history is wholly unknown. ”

“ And yet, forsooth, we are asked, upon the conflicting testimony of a multiplicity of boiled infusions, yielding often even in the same hands uncertain results, and in different hands conflicting ones, to believe that organic Nature—whose method of reproduction is the same to the very limits of certain knowledge—changes its method in this uncertain and cloudy region. ”

“ The mastic-particles are almost infinite in number, and must crowd the entire field of the microscope; but they are as absolutely ultra-microscopic as though they had no existence. I have tested this with an exquisite 1/50 of Powell and Lealand's, employed with a new and delicate mode of illumination for high powers, [9] and worked up to 15,000 diameters; but not the ghostliest semblance of such particles was seen. ”

“ At the expiration of five days they were again examined, and one or other of the monads was found in every successive "dip."
Now let it be observed that there can be no possible error as to the forms. They were the identical species of the maceration, with which I am as familiar as with a barn-door fowl. What, then, is the logic of these facts? Dr. Tyndall proves that bacteria only develop in sterilized infusions when the air around them is laden with motes of incalculable multitude and exquisite minuteness. ”

“ From this, and associated indications, he acutely inferred that "the power of developing life by the air, and its power of scattering light, would be found to go hand in hand;" so that a beam of light sent across the air into which infusions might be placed and examined by the eye, rendered sensitive by darkness, might be utilized with the best results in determining the existence of bacteria-germs. To bring the idea to ”