NA TURE 



[September 12, 1901 



quagga hybrid) by Agasse, a very trustworthy animal painter of the 

 early part of last century. In the drawing of the filly the mane 

 is represented as lying to one side, as in Arabs and other well- 

 bred horses. The pictures (now in the Museum of the Royal 

 College of Surgeons, London) were made because the subsequent 

 foals were believed to prove the truth of the "infection" doc- 

 trine. Had the mane of the filly been erect it would hardly 

 have escaped the keen eyes of the artist. But had Agasse by 

 any chance missed this all-important detail. Lord Morton or 

 some of those interested would doubtless have called his attention 

 to the matter. If the mane of an Arab is completely removed 

 early in the spring it is stifif, and upright in the autumn, but 

 hanging to one side close to the neck ;in the following summer. 

 When the whole circumstances are taken into consideration, there 

 seems to me no escape from the conclusion that the mane of the 

 filly was upright when seen by Lord Morton i« August, 1S20, 

 and lying to one side when painted by Agasse the following 

 summer, because it had been regularly cropped or at least 

 hogged some months before Lord Morton's visit. But whatever 

 be the explanation of the want of agreement between the mane 

 as seen by Lord Morton and as depicted by Agasse, it will, I 

 think, be admitted that the evidence afforded by the mane of 

 the filly is hardly sufficient to establish the truth of the doctrine 

 of telegony. Of still less value is the evidence afforded by the 

 make, coat, colour and markings which were apparently too 

 indistinct 10 deserve the name of stripes. The colts were 

 decidedly Arab-like, of a bay colour marked more or less " in a 

 darker tint." Judging from Agasse's drawings they closely 

 resemble Arab-Indian crosses ; they are, in fact, in make very 

 like the Arab-Kattiawar horse already referred to. I have 

 seen a bay Highland cob with as many stripes as Lord 

 Morton's colts, and pure-bred Arabs of a dun colour 

 with stripes on the neck and far more distinct leg 

 bars than those depicted by Agasse. I believe the colts 

 owed their stripes and colour not to " infection " of their dam 

 by her previous mate the quagga, but to reversion. It is quite 

 possible the black Arabian horse was of mixed origin ; that the 

 chestnut mare was crossbred is admitted. As in the west of 

 Ireland the offspring of black and chestnut ponies are sometimes 

 of a decidedly dun colour, it is not surprising that the black 

 Arab and the half-bred chestnut had bay offspring. Neither 

 are the stripes surprising. I recently ascertained that the chest- 

 nut mare was presented to Lord Morton (while serving with his 

 regiment in India) by one of his officers — Mr. Boswell, of Dee- 

 side, Aberdeenshire — and that she was most likely a cross be- 

 tween an Arab and a country-bred pony. In Kattiawar the 

 ponies when pure-bred are of a rufous grey colour and more or 

 less richly striped. If in the chestnut mare there was any 

 Kattiawar or even any native pony blood its offspring to a black 

 sire might have been expected to be of a dun colour and striped. 

 In a word, there is no reason for assuming that the foals would 

 have been less striped if the chestnut mare had been mated with 

 the black Arab first and the quagga afterwards. 



By way of testing the truth of the "infection" doctrine I 

 started, in 1S95, a number of experiments, and especially 

 arranged to repeat as accurately as possible, what is commonly 

 called Lord Morton's experiment. Since then twelve mares 

 after producing sixteen zebra hybrids, a mule, and a hinny have 

 had an opportunity of supporting the telegony hypothesis by 

 giving birth to twenty-two pure-bred foals. 



During the same period Baron de Parana of Brazil has bred 

 at least six zebra hybrids, and some of the dams of these hybrids 

 subsequently produced ordinary foals. Further, Baron de 

 Parana has for a number of years been engaged in crossing 

 cattle and in watching the results obtained in several mule- 

 breeding establishments, where from 400 to 1000 brood mares 

 are kept. As in these establishments the mares breed mules 

 and horses alternately — two or three mules and then a horse 

 foal— there has been carried on for some years, under the ob- 

 servation of Baron de Parana, a telegony experiment on a 

 gigantic' scale. 



The single hybrid bred by Lord Morton had extremely few 

 stripes, and only in a remote way suggested a member of the 

 zebra family. AH my hybrids, like those bred in Brazil, have 

 more stripes than their zebra sire, and in some of them the 

 bands are nearly as conspicuous as in some of the zebras, thus 

 proving that both the mares (which varied in colour and breed) 

 and the two zebra stallions used were well adapted for the ex- 

 periment. The results of my experiments, not only with the 

 Equidte but also with other domestic quadrupeds and birds, all 



NO. 1663, VOL. 64] 



point to the conclusion that there is no such thing as telegony, 

 and the same conclusion has been independently arrived at by 

 Baron de Parana in Brazil. Believers in telegony — they are 

 numerous in America, India, and Australasia, as well as in Eng- 

 land — almost always say of the many experiments recently made 

 with a view to giving "infection" a chance of showing itself 

 that they have only yielded negative results, and they generally 

 add, it is impossible to prove a negative. After carefully con- 

 sidering all the more striking so-called cases of " infection," I 

 have no hesitation in saying that there is no satisfactory evidence 

 that there has ever been, either in the human family or amongst 

 domestic animals, a single instance i:>f infection. 



I have in a hurried and imperfect manner indicated that we 

 are not likely to find either in maternal impressions, the direct 

 action of the environment, use-inheritance, or telegony a true 

 cause of variation. I have endeavoured to point out that, 

 instead of simply stating that variation is due to the constant 

 recurrence of slight inequalities of nutrition of the germ-cells, 

 we may with some confidence assert that differences in the age, 

 vigour, and health of the parents and differences in the ripeness 

 of the germ-cells are potent causes of variation. 



I have also endeavoured to prove that intercrossing, though 

 a direct cause of retrogressive variation, is only an indirect 

 cause of progressive variation, while interbreeding (in-and-in- 

 breeding) at the right moment is a cause of progressive variation. 



Further, I have discussed at some length the swamping effects 

 of intercrossing, chiefly with the object of showing (i) that 

 progress in a single direction is probably often due to new 

 varieties swamping old, it may be long established, varieties ; 

 and (2) that several varieties may be sufficiently exclusive to 

 flourish side by side in the same area, and eventually (partly 

 owing to their aloofness, i.e., to differential mating) give rise to 

 several new species. 



I have only now to add that I was mainly led to select "The 

 Experimental Study of Variation " as the subject of my address 

 that I might indirectly indicate that the time had come when 

 a well-equipped institute should be provided for biological and 

 other experiments. 



NOTES. 



The Times announces that the Indian Government have 

 adopted the suggestion of the Royal Society for the carrying out 

 of a magnetic survey. The existing magnetic observatories at 

 Bombay and Calcutta being inadequate as base stations for the 

 vast area the survey will cover, similar observatories are in 

 course of construction at Dehra Dun, at Kodaikanal, and at 

 Rangoon. The Dehra Dun observatory will be under the 

 supervision of Colonel Gore, R.E. , the Surveyor-General of the 

 Indian Survey (whose headquarters are located there) ; but the 

 other four will be in charge of Mr. John Eliot, the meteorological 

 reporter to the Government. The .Survey and Meteorological 

 Departments will, in fact, be jointly responsible for the investi- 

 gations. The field observations will be carried out by .six or 

 seven detachments of the Survey Department, and these will be 

 controlled by Captain Fraser, R.E., who has recently been 

 arranging in England for the purchase of the necessary instru- 

 ments. .Sind and the Punjab will first be taken in hand ; and, 

 as the country is now intersected with railways in all directions, 

 enabling field detachments to quickly cover the distances from 

 one observing station to another, it is anticipated that five years 

 will suffice to complete the field work of the preliminary 

 magnetic survey. 



It is stated that a committee is being formed at Amalfi to 

 arrange for the celebration of the fourth centenary of the inven- 

 tion of the compass. The Duke of the Abruzzi has agreed to be 

 president of the committee, and Signor Morin, the Minister of 

 Marine, the vice-president. The celebration will take place 

 next year. 



To obtain information for the Lightning Research Committee 

 organised by the Royal Institute of British Architects and the 

 Surveyors' Institution, the Institution of Electrical Engineers has 



