But this is precisely what cannot be done, for one of the most conclusive results of modern research has been to show that in the present world spontaneous generation never occurs, that living things come only from living parents, and that from organic matter alone can the smallest particle of organic matter be derived. _Omne vivum e vivo, omnis cellula e cellula, omnis nucleus e nucleo._ Upon this point there is now complete agreement amongst scientific authorities, and what is most remarkable, none are more strenuous in upholding the doctrine of _Biogenesis_,[74] than some of those who with equal vehemence proclaim the doctrine of Evolution for which the occurrence of spontaneous generation is a necessity. Never, for example, were there Evolutionists more pronounced than Professors Huxley and Tyndall, and they both saw clearly that without spontaneous generation there could not have been evolution such as they maintained. Yet when the occurrence of spontaneous generation, here and now, was asserted by Bastian and Burdon Sanderson, they, following in the wake of Pasteur, repudiated the notion, and Tyndall in particular conclusively disproved the experiments by which it was supported.[75] As Huxley wrote to Charles Kingsley:[76] I am glad you appreciate the rich absurdities of spontogenesis. Against the doctrine of spontaneous generation in the abstract I have nothing to say. Indeed it is a necessary corollary from Darwin's views if legitimately carried out. A few years later, writing to Dr. Dohrn[77] upon the same subject, he made use of a phrase--which in his mouth expressed the uttermost limit of disbelief: "Transubstantiation will be nothing to this if it turns out true." In the same year as President of the British Association he chose for the subject of his inaugural address, "Biogenesis and Abiogenesis," and, after a careful examination of the case for each, pronounced the former "to be victorious all along the line." In spite of all this, however, he assured himself as an Evolutionist that spontaneous generation must once have been not only a possibility but a fact. In the same Presidential address, after piling up evidence against it--he thus continued:[78] But though I cannot express this conviction of mine too strongly, I must carefully guard myself against the supposition that I intend to suggest that no such thing as Abiogenesis has ever taken place in the past, or ever will take place in the future. With organic chemistry, molecular physics and physiology yet in their infancy, and every day making prodigious strides, I think it would be the height of presumption for any man to say that the conditions under which matter assumes the properties we call "vital" may not, some day, be artificially brought together. All I feel justified in affirming is that I see no reason for affirming that the feat has been performed yet.