Part 9

The second theory which attempts to account for the phenomenon of telegony is termed the saturation hypothesis. In the words of Mr. Bruce Lowe, who has formulated the theory, we may say that, ‘briefly put, it means that with each mating and bearing 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.’ Although not very well expressed, it is obvious what the author means; and if this saturation really takes place, it accounts for a good deal more than telegony. It would affect the whole body and nature of the dam, and not only the reproductive organs, which, according to Romanes and others, are alone influenced. There is no doubt that matter can and does pass from the blood of the embryo into that of the mother--in certain classes of mammalia, at any rate. The published Report of the Fourth International Congress of Zoology, which met in 1898 at Cambridge, contains a paper by Professor Hubrecht, of Utrecht, in which he describes certain blood-corpuscles formed in the embryo which undoubtedly make their way into the maternal bloodvessels and take part in her circulation. That matter can pass from the bloodvessels of the embryo to those of the mother is further demonstrated by the experiments of M. Charrin, who showed that diphtheritic toxins injected into the embryos of a rabbit caused the death of the mother within five days, and further that a rabbit can be rendered immune by injecting anti-diphtheritic toxins into the embryos.

There is nothing in these experiments to show that the nature of the dam is radically altered; and in the Equidæ, in which, as we have seen, the classical case of telegony occurred, there is a strong presumption against any such transference of blood-corpuscles from the embryo to the mother. Still, taking all the facts into consideration, it appears that, if telegony exists, it is more likely to be brought about by saturation than by the direct infection of the ovary; though, if the former method be accepted, telegony must be confined to the mammals and the comparatively few other animals whose young spend some time in the body of the mother and are not hatched out from eggs which have lost their connexion with the body of the mother at an early stage.

Before passing on to consider the views of those who hold that telegony does not exist and to see what light the Penycuik experiments throw on the subject, a word or two may be said about Mr. Herbert Spencer’s theory of the mode in which telegony, in which he firmly believed, is brought about. He suggested that some ‘germ-plasm’ passes from the embryo into the mother and becomes a permanent part of her body, and that this is diffused throughout her whole structure until it affects, amongst other organs, the reproductive glands. This view, which in some respects recalls the pangenesis of Darwin, is intermediate between the saturation and the infection hypotheses. Professor Ewart refers to it as ‘indirect infection.’

Weismann, to whom we owe the term telegony, came to consider the facts for and against its existence in connexion with his well-known inquiry into the inheritance of acquired characters. If telegony be true, there is no need to look further for a clear case of the inheritance of a character which has been acquired during the lifetime of the parent. The quagga-ness--if one may be permitted to use such an expression--of Lord Morton’s mare was acquired when she was put to the quagga or shortly afterwards, and was transmitted to her foals. A clearer case of a character acquired during lifetime and transmitted to offspring could not be imagined. Weismann does not absolutely deny the possibility of the existence of telegony, but he would like more evidence. In the Contemporary Review he writes: ‘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.’ And further: ‘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 would, in fact, refer the case to reversion, and quotes Settegast to the effect that every horse-breeder is well aware that the cases are not rare when colts are born with stripes which recall the markings of a quagga or zebra. We shall return to this point later.

A considerable number of German breeders support the contention of Weismann that telegony is as yet unproven, and it may be pointed out that in Germany, on the whole, breeders have had a more scientific education than in England, and that in that country science is regarded with less aversion or contempt than is usually the case among so-called practical men in England. Settegast has been quoted above: neither he nor Nathusius, a leading authority on domestic cattle, has ever met with a case of telegony, and the same is true of Professor Kühn, the late Director of the Prussian Agricultural Station at Halle. We may mention one more case of an experienced breeder who was equally sceptical--the late Sir Everett Millais, who was, as is well known, an authority of great weight in the matter of dog-breeding. He writes as follows, in a lecture entitled ‘Two Problems of Reproduction’:

‘I may further adduce the fact that in a breeding experience of nearly thirty years’ standing, during which I have made all sorts of experiments with pure-bred dams and wild sires, and returned them afterwards to pure sires of their own breeds, I have never seen a case of telegony, nor has my breeding-stock suffered. I may further adduce the fact that I have made over fifty experiments for Professor Romanes to induce a case of telegony in a variety of animals--dogs, ducks, hens, pigeons, etc.--but I have hopelessly failed, as has every single experimenter who has tried to produce the phenomenon.’

It is thus evident that there was a considerable body of opinion, both practical and theoretical, for and against telegony; and that a re-investigation of the subject was urgently needed. Such a re-investigation has been begun by Professor Ewart at Penycuik. Since the clearest and most definite evidence of this throwing back to a previous sire is derived from the crossing of different species of the Equidæ, it was desirable to repeat the experiment of Lord Morton. This is now unfortunately impossible, because the quagga is extinct. The zebra is, however, still with us, and the mating of a zebra stallion with every variety of horse, pony, and ass, and subsequently putting the dam to pure-bred sires, has been the more important part of the numerous experiments carried on in the Midlothian village some ten miles southwest of Edinburgh.

Before considering in detail the result of the experiments it will be necessary to say a few words on the question of the various species of zebra; and since, like Weismann, Professor Ewart explains certain of the phenomena attributed to telegony by reversion, it will be as well to inquire how far reversion is known amongst the Equidæ, and what evidence we have that the ancestor of the horse was striped.

Matopo, the zebra stallion from which Professor Ewart had, some eight years ago, bred eleven zebra-hybrids from mares of various breeds and sizes, belongs to the widely distributed group of Burchell’s zebras. Many sub-species or varieties are included in this group, which, as regards the pattern of the stripes, passes--in certain varieties found in Nyassaland--into the second species, the mountain zebra, once common in South Africa. The third species is the Grévy’s zebra of Shoa and Somaliland; it is probably this species which attracted so much attention in the Roman amphitheatres during the third century of our era. A pair of Somali zebras were presented to the late Queen some years ago by the Emperor Menelik, and for a time were lodged in the Zoological Gardens, Regent’s Park. This species measures about fifteen hands high, is profusely striped, and stands well apart from the other two groups. It is important to note that in Professor Ewart’s opinion it is the most primitive of all the existing striped horses.

There is no direct evidence that the ancestors of horses were striped. Certain observers think that some of the scratches on the life-like etchings on bone, left us by our palæolithic cave-dwelling ancestors, indicate such stripes; but little reliance can be placed on this. On the other hand there is much indirect evidence. Every one who has an eye for a horse, and who has travelled in Norway, is sure to have noticed the stripings, often quite conspicuous, on the dun-coloured Norwegian ponies. Colonel Poole assured Darwin that the Kathiawar horses had frequently ‘stripes on the cheeks and sides of the nose.’ Breeders are well aware that foals are often born with stripes, usually on the shoulders or legs, less frequently on the face. Such stripes as a rule disappear as the colt grows up, but can often be detected in later life for a short time after the coat has been shed; they are sometimes only visible in certain lights, and then produce somewhat the same impression as a watered silk. From the facts that more or less striped horses are found all over the Old World; that in Mexico and other parts of America the descendants of horses which were introduced by the Spaniards and which afterwards ran wild are frequently dun-coloured and show stripes; that foals are frequently striped; and that mules not uncommonly have leg and shoulder stripes, the inference is largely justified that the ancestors of all our horses were striped.

The hypothesis of reversion has recently been called in question, and no doubt the term has been much abused. Animals and plants have been said to revert to some remote ancestor when they have varied in some particular, and this variation has then been described as a primitive character possessed by the ancestor; thus there has been much arguing in and about a vicious circle. But the fact that a term has been illogically applied does not destroy the existence of that which the term signifies, and there can be no doubt that reversion exists. That it exists in the Equidæ is shown by the following proofs: (1) The ancestors of the horse had four premolar teeth in the upper jaw; the modern horse has lost, or is losing, the first of these, and as a rule has only three. When the first is present--the so-called wolf-tooth--it is small, and soon disappears. Zebras usually retain the ancestral number. A few years ago Professor Ewart had a Shetland pony in which the first premolar was relatively nearly as large as it is in hipparion, one of the supposed ancestors of the horse. (2) There is no doubt that the horse is descended through three-toed ancestors from five-toed ancestors. All trace of the latter condition is now lost in development, but an embryo horse six weeks old has three toes as completely formed as those of a rhinoceros. The outer toes then begin to dwindle, and the newly-born foal supports itself on its central digit alone; but horses are occasionally born with two digits, each encased in a hoof, and at very rare intervals with three. Cæsar’s favourite horse was polydactylous, and so was Alexander’s Bucephalus. Major Waddell, in his book on the Himalayas, refers to a creamy fawn-coloured pony, which ‘had a black stripe down the spine ... broad black stripes over the shoulders, flanks, and legs, and dappled spots over the haunches.’ Many other instances might be quoted, but enough has been said to show that reversion is found in the Equidæ, as in other families of animals.

We now pass to the experiments made at Penycuik in crossing the zebra Matopo with various mares of different breeds.

1. Matopo was first mated with Mulatto, one of Lord

To face page 84.]

Arthur Cecil’s black West Highland ponies. The result was the hybrid Romulus, which on the whole, both in mental disposition and bodily form, took more after his father than his mother. His striping was even more marked than that of his sire. He had a semi-erect mane, which was shed annually. The pattern of the markings, on both body and face, resemble the stripes on a Somali zebra--which, as we have seen, is regarded by Professor Ewart as the most primitive type--more than they resembled that of any of Burchell’s zebras. The profuse striping is a point of difference between this hybrid and Lord Morton’s. The quagga-hybrid was less striped than many dun-coloured horses (see illustration).

The mother Mulatto was next mated with a highly-bred grey Arab horse, Benazrek. The offspring agreed in all respects with ordinary foals; it had, however, a certain number of indistinct stripes which could only be detected in certain lights. The stripes were not nearly so clear as in a foal bred by Mr. Darwin from a cross-bred bay mare and a thoroughbred horse, and they disappeared entirely in about five months.

Mulatto has produced a third foal to Loch Corrie, a sire belonging to the Isle of Rum group of West Highland ponies, and closely resembling its mate. This foal was about as much striped as its immediate predecessor. In both cases the pattern of the stripe differed not only from that of Matopo, the previous sire, but from that of the hybrid Romulus. These two foals seem to lend some support to telegony; but the evidence which might be drawn from the second of them is destroyed by the fact that the sire, Loch Corrie, has produced foals from two West Highland mares, one brown and one black, and each of these foals has as many and as well-marked stripes as the foal of Mulatto.

2. Four attempts were made to cross the zebra with Shetland ponies: only one succeeded. The hybrid was a smaller edition of Romulus. The dam Nora had been bred from before, and had produced by a black Shetland pony a foal of a dun colour which was markedly striped. After the birth of the hybrid she was put to a bay Welsh pony; the resulting foal had only the faintest indication of stripes, which soon disappeared. It is a remarkable fact that Nora’s foals were more striped before she had been mated with the zebra than afterwards.

3. Five Iceland ponies were mated with Matopo, of whom one produced, in 1897, a dark-coloured hybrid. The dam, Tundra, was a yellow and white skewbald, which had previously produced a light bay foal to a stallion of its own breed. Her third foal (1898) was fathered by a bay Shetland pony, and in coloration closely resembled its dam. There was no hint of infection in this case. In 1899 Professor Ewart bred from this mare, by Matopo, a zebra-hybrid of a creamy fawn colour, and so primitive in its markings that he believes it to stand in much the same relation to horses, zebras, and asses as the blue-rock does to the various breeds of pigeons (see illustration).

4. Two Irish mares, both bays, produced hybrids by Matopo, and subsequently bore pure-bred foals. One of the latter was by a thoroughbred horse, the other by a hackney pony. The foals were without stripes, and showed no kind of indication that their mother had ever been mated with a zebra.

5. Although Professor Ewart experimented with seven English thoroughbred mares and an Arab, he only succeeded in one case. The mare produced twin hybrids, one of which, unfortunately, died immediately after birth. In the summer of 1899 the same mare produced a foal to a thoroughbred chestnut; ‘neither

To face page 86.]

in make, colour, nor action’ does it in any way resemble a zebra or a zebra-hybrid.

6. A bay mare which had been in foal to Matopo for some months miscarried. Here--if there is anything in the direct infection theory--the unused germ-cells of the zebra had a better chance than usual of reaching the ova from which future offspring are to arise, yet neither of the two foals which this mare subsequently produced to a thoroughbred horse ‘in any way suggests a zebra.’

The above is the record of the successful experiments which have been tried at Penycuik, with a view of throwing light on the existence of telegony in the Equidæ. Experiments have also been made with other animals, such as rabbits, dogs, pigeons, fowls, and ducks. Space allows us to quote but one. Six white doe rabbits, all of which had borne pure white offspring to white bucks, were crossed with wild brown rabbits. The result was forty-two young rabbits, all of a bluish-black colour, which in a very short time turned to a brown. These, at the time of writing, were about half grown, and Professor Ewart tells us that it was almost impossible to distinguish them from a full-blooded wild rabbit kept in the same enclosure. The half-breeds, however, were tamer and slightly lighter in colour. The mother does next bred with white bucks again, and in every case bred true. The pure white young showed no trace of throwing back to a previous sire.

A phenomenon somewhat similar to telegony, and one which seems at present quite unexplained, is that a hen which has been crossed with a cock of another breed often lays eggs whose shell is no longer like that of its own breed, but in colour, and frequently in texture, resembles that of the breed with which it has been crossed. Mr. Bulman has recorded a case of this in the pages of ‘Natural Science.’ Some Orpington fowls which laid eggs of a buff tint were allowed to run loose in a large yard with fowls of various breeds. After a few months they were confined in separate pens again, and for several weeks afterwards they continued to lay white eggs. There seems to be no doubt of the existence of this curious phenomenon; it is mentioned by Gadow in his volume on ‘Birds,’ in Bronn’s ‘Thierreich,’ by Nathusius in the Journal für Ornithologie, and in Newton’s ‘Dictionary of Birds.’ When one calls to mind that the shell is deposited by a special shell-gland which is in no way connected with the ovary, but is a part of the quite distinct oviduct, and that the change in the colour of the eggshell must be caused by some change brought about in this gland by cross-fertilization, we begin to recognize how mysterious and inexplicable are many of the problems which affect breeding.

Throughout his account of his experiments Professor Ewart is extremely cautious in claiming to prove anything, but we think he has justified his claim to have shown that telegony by no means always occurs, as many breeders believe. His experiments so far support the view of Continental mule-breeders that telegony, if it takes place, occurs very seldom. But the experiments are not complete, and it is much to be hoped that they may be continued. If it should subsequently appear that out of fifty pure-bred foals from dams which have been previously mated with the zebra no single instance of telegony be found, the doctrine may surely be neglected by breeders; and if in the experiments which are now being carried out with various other mammals and birds telegony does not occur, the doctrine may be relegated to what the Americans would term the ‘dumping-ground’ of old superstitions. The present state of the matter may be summed up in the Professor’s own words: ‘The experiments, as far as they have gone, afford no evidence in support of the telegony hypothesis.’ Nothing has occurred which is not explicable on the theory of reversion.

Partly owing to a certain doubt or distrust which has recently been expressed as to the existence of reversion, and no doubt partly because it is reasonable to hold that the phenomena of telegony may all be referred to reversion, Professor Ewart has made some direct experiments on this subject. Darwin, Tegetmeier, and many others have made numerous breeding experiments on pigeons, with the result that we may say that the crossing of extreme forms usually tends to reversion in the offspring. The ancestor of the domestic pigeon is known with tolerable certainty to have been the blue-rock pigeon, Columba livia. By crossing a male barb-fantail and a female barb-spot Darwin produced a bird ‘which was hardly distinguishable from the wild Shetland species’ of blue-rock. In his description of this experiment, Darwin, as Weismann points out, confines himself chiefly to the coloration: he does not inquire how far reversion also appears in the structure of the bird. This question has been answered by one of Professor Ewart’s many experiments with pigeons. He crossed a white fantail cock with the offspring of an owl and an archangel. The fantail was pure white, with thirty feathers in its tail, and was so prepotent as to produce white offspring when mated with blue pouters. The owl-archangel was more of an owl than an archangel. One of the young of this complex pair had the coloration of the Shetland rock pigeon, which has a white croup and the wings in front of the bars a uniform blue; the other resembled the Indian rock pigeon in having a blue croup and the front part of the wings chequered. In this second bird there was complete reversion as to colour, and in the first, wherever measurements were possible, there was practically complete reversion also as to form. ‘In its measurements it is relatively almost identical with a typical Shetland blue-rock.’ The tail feathers are twelve in number, and show but the faintest indications of any colour-inheritance from their immediate parents. An additional point of interest is that in disposition this bird seems wilder and more shy than the domesticated breeds usually are. It is vigorous and hardy, and is much admired by the fanciers.