From time to time it has been said by breeders of horses and other animals that females, having bred to certain sires, have subsequently thrown offspring to other sires which in outward form, colour, etc, have taken after the sire to which they had first been pregnant, or in other words, that the influence of the first male is sometimes shown in the produce when the mare is put to a different mate. To illustrate the proposition- - a mare having bred to a donkey, her subsequent produce to a horse should present some of the characters of the donkey. In explanation it is suggested that the unripe eggs in the ovary of the mare at the time of the first impregnation, as well as the one which is fertilized, are infected with the germinal matter of the first sire, and rendered capable of producing foals to other horses more or less like him; or, as Bruce Lorre puts it, " the dam absorbs some of the nature or actual circulation of the yet unborn foal, until she eventually becomes ' saturated' with the sire's nature or blood as the case may be".
What has hitherto been regarded as the most authentic and convincing experiment in this connection was performed by Lord Morton in the early part of the nineteenth century. He put a chestnut mare, which had never before bred, to a quagga stallion, and as a result obtained a female hybrid of a dun colour which " in her form and colour bore very decided indications of her mixed origin". The same mare subsequently passed into the hands of Sir George Ouseley, who put her to a black Arabian horse two consecutive years, and produced a filly and a colt respectively which in their colour and in the hair of their manes, it is said, bore a striking-resemblance to the quagga. Both were bay, and distinguished by a " dark line along the ridge of the back, the dark stripes across the forehead, and the dark bars across the back part of the legs. The stripes of the colt were confined to the withers and to the part of the neck next to them. Those on the filly covered nearly the whole of the neck and the back as far as the flanks. The colour of her coat on the neck adjoining to the mane was pale and approaching to dun, rendering the stripes there more conspicuous than those on the colt. The same pale tint appeared in a less degree on the rump, and in this circumstance of the dun tint also she resembled the quagga. . . . Their manes were black, that of the filly short, stiff, and stood upright, and that of the colt long, but so stiff as to arch upwards and to hang clear of the sides of the neck, in which circumstance it resembled that of the hybrid."
Prima facie this would appear to admit of the conclusion that impregnation by the quagga had in some way or other imbued the system of the mare from which these two foals were bred, with the power to impress upon her subsequent offspring by other sires the characters which distinguished her first mate, the quagga.
However inviting such a conclusion may be, the fact, as mentioned by Darwin, must not be overlooked that " in all parts of the world, stripes of a dark colour frequently appear along the spine, across the legs, and on the shoulders occasionally, where they are double or treble, and even sometimes on the face and body, of all breeds of horses and of all colours". Notwithstanding this, Darwin was satisfied that in the case of Lord Morton's experiment " the quagga had affected the character of the offspring subsequently got by the black Arabian horse".
The evidence which that distinguished observer, Mr. Herbert Spencer, was able to procure, satisfied him of the truth of the influence of the male on the progeny subsequently borne by the mother to other males, and he suggests that this remarkable phenomenon is the result of the ova in the ovaries becoming infected with germ-plasm through her tissues.
From experiment and other sources of information, Mr. Romanes was equally satisfied that a previous sire "asserted his influence in a subsequent progeny ", but he was of the opinion that instances of the kind were of rare occurrence.
Mr. Allison, who writes for the Sportsman under the nom de plume of the " Special Commissioner", avers that it would " not be difficult to furnish hundreds or even thousands of instances" of the occurrence. Whether the cases referred to by Mr. Allison would bear that searching method of enquiry which science demands before deciding upon so delicate and obscure a question, there is no evidence to show. Some breeders of horses, dogs, and other animals claim to have experienced the effects of telegony in their studs and kennels, but it is doubtful if their knowledge of the possible influence of reversion and other cognate subjects was sufficiently extensive to permit of their forming a reliable judgment.
In this connection Professor Ewart points out that while many English breeders have been it may be over-credulous, not a few German breeders have long looked with suspicion on the infection theory. " Professor Kuhn (late head of the Prussian Agricultural station at Halle), Settegast, Nathusius, and others familiar with scientific methods, notwithstanding an extensive experience in breeding and crossing, have never known a case of telegony. Hence it would appear that while some doubt its ever occurring, others are convinced there is no such thing as telegony, that the female is neither infected by the first male, nor by subsequent mates to which she bears offspring."
Professor Ewart, who has made the subject of telegony a special study for several years, employing in his experiments Burchell's male zebra, which he has crossed with several varieties of the horse, and subsequently mated the mares so used with horses, believes in regard to markings that " if those on Sir George Ouseley's colts were not due to the clam having been influenced in some way by the quagga, they resulted from reversion". "I prefer", he says, "the reversion explanation, because it seems to be simpler and more in accordance with established facts." On the general question, however, he is careful to note that " it would be premature to come to any conclusion as to whether there is such a thing as infection of the germ or not".