There is no how I could reconcile such cases with my theory. simpler supposition than that spermatozoa occasionally reach the ovary, and there enter into some of the immature eggs. Amphimixis cannot proceed, as the germ-plasm of the egg is not ripe, but the nucleus of the sperm-cell continues to live in certain circumstances, and so remains till the time of a subsequent coitus with another mate. "If this occurred some time after the first of the offspring was born, it might easily have coincided approximately with the second coitus, to which the fertilisation would then apparently be due." With this indication of an explanation I thought to be content and went on as follows: "If the infection' were proved beyond a doubt, a supplementary fertilisation of an egg-cell in this manner must be considered possible; we certainly might then reasonably ask why mares, cows, or sheep, should not occasionally become pregnant without being covered a second time. But this has never yet been known to occur, and I incline to Settegast's view that there is no such thing as an 'infection' of this kind, and that all the instances which have been recorded and discussed critically by him are based upon a misconception." * I must say that to this day, and in spite of the additional cases brought forward by Spencer and Romanes, I do not consider that telegony has been proved-even though I thus lay myself open to Mr. Spencer's suspicion that I am not only ready" to base conclusions on things it is easy to imagine" but "reluctant to accept testimony which it is difficult to doubt." I do not dispute the possibility of telegony; I grant that the wide general acceptance of the belief in the past has so impressed me that I have always said that possibly it might be justifiable and founded on fact. In like manner the "rust" of corn (Puccinia graminis) was regarded by peasants as being somehow caused by the barberry, long before De Bary succeeded in raising the tradition to the rank of a scientific fact, by showing that the fungus on the corn and the Ecidium berberidis on the leaves of the barberry are the alternate generations of one plant. So I consider it inexpedient to reject such popular traditions without consideration; and I should accept a case like that of Lord Morton's mare as satisfactory evidence, if it were quite certainly beyond doubt. But that is by no means the case as Settegast † has abundantly proved. He does not doubt that" after the mare had borne a hybrid to a quagga, she subsequently had colts by a horse, and that these were marked with stripes on the neck, withers, and legs"; but he contends that there were no other characteristics of the quagga discernible in the colts: in the drawings by Agasse in the Royal College of Surgeons, London, "the liveliest imagination would not avail to find any semblance to the form of the quagga." The stripes do not in them "Keimplasma," p. 507; Eng. Ed., p. 386. † H. Settegast: "Die Thierzucht": Breslau, 1878. Vol. i. p. 225. selves, Settegast thinks, amount to proof, "for every experienced horsebreeder knows" that " cases are not very rare in which colts are born with stripes that recall those of the quagga or zebra. They regularly disappear as the colts increase in age." Such an experienced breeder as Nathusius remarks as to this: "A spotless light brown mare that I had, whose sire was Dan Dawson, produced first, one after another, five spotless colts by the thoroughbred stallion Belzoni, and subsequently two spotless colts by the trotting-horse Schultz; the eighth colt, whose sire was a white horse, Chiradam, was at its birth of a dusky dun colour, with dark stripes on the back; and on the knee and hock it showed dark zebra-like bands which were much more distinct than those that occurred on Lord Morton's colt; but in a year these marks had disappeared, and the horse was white like its father." Moreover, experiments have been made with a view to proving the occurrence of telegony, as I see from a note in Settegast's book (p. 226). A Herr Lang of Stuttgart has for twenty years experimented with dogs, without, however, ascertaining "a single fact that could be made use of for the advancement of the infection theory.' Of course, in such a case negative results prove nothing; and the attempt must be made to determine the truth by new experiments. But as hitherto there have been no positive results from the observations that have been made; and as the most competent judges, namely, breeders who have a scientific knowledge, such as Settegast and Nathusius, and the late head of the Prussian Agricultural Station at Halle, Professor Kühn, spite of their extensive experience in breeding and crossing, have never known a case of telegony, and therefore have great doubt as to its reality; it seems to me that according to scientific principles, only the confirmation of the tradition by methodical investigation, in this case by experiment, could raise telegony to the rank of a fact. With this I may close my reply to Herbert Spencer, though he has stated several other objections, which it would not be uninteresting to discuss. But the space at my disposal is limited, and the questions at issue involve many considerations, and cannot be disposed of in a few words. I hope to return to them in a subsequent treatise. If I have not the good fortune to convince my opponent-the usual event of controversial encounters--perhaps, at any rate, the unbiased reader will grant that my opinions are not without foundation; and I am content to leave the future to decide whether, and how far, they will become an indisputable and sure possession of science. They have already borne good fruit, for they have opened up new fields for research; and it is my hope that they will continue to stimulate progress. AUGUST WEISMANN. |