208 THE PHYSIOLOGY OF REPRODUCTION 



in which many practical breeders still believe, was called Telegony 

 or Infection, and the female was said to be " infected " by the 

 previous sire. 



The classical example, and one in which Darwin 1 himself believed, 

 of the supposed influence of a previous sire upon the future offspring, 

 is the case of Lord Morton's quagga, which was stated to have 

 infected an Arab mare, so that she subsequently produced two striped 

 colts by a black Arab horse. In recent years Ewart 2 has repeated 

 the experiment, employing a Burchell's zebra and a number of 

 different mares. These experiments were supplemented by others in 

 which animals of various kinds were used. As a result of his 

 investigations he has come to the conclusion that there is no evidence 

 for the existence of Telegony. A microscopic examination of the 

 . structure of the hairs of the subsequent foals bred by Professor Ewart 

 provided further negative evidence. 3 Minot, 4 also, in a series of experi- 

 ments upon guinea-pigs, found no indication of any telegenic influence. 

 Moreover, Karl Pearson, 5 as a result of an extensive statistical inquiry, 

 was unable to discover any evidence of telegony in man. 6 



EFFECT OF EXTERNAL CONDITIONS AND OF THE SOMA ON THE 



GERM-CELLS 



Attempts have been made by Stockard 7 and by Pearl 8 to modify 



1 Darwin, The Variation of Animals and Plants under Domestication, Popular 

 Edition, vol. i., London, 1905. 



- Ewart, The Penicuik Experiments, London, 1899. 



3 Marshall, "On Hair in the Equidae," Proc. Roy. Soc. Edin., vol. xxiii., 1901. 



4 Minot, "An Experiment with Telegony," British Assoc. Reports, Cambridge 

 Meeting, 1904. 



'"' Pearson, The Grammar of Science, 2nd Edition, London, 1 900. 



(i According to Kohlbrugge spermatozoa may penetrate the epithelium 

 of the uterine mucosa (in the mouse, rabbit, bat, etc.), and he suggests that they 

 may even unite with epithelial cells. These observations are advanced as a 

 possible explanation of Telegony. (Kohlbrugge, " Der Einfluss der Spermato- 

 zoiden auf den Uterus ; ein Beitrag zur Telegonie," Zeitsch. f. Morph. und 

 Anthrop., vols. xii. and xiii., 1910 and 1911.) Waldstein and Eckler maintain 

 that the absorption of spermatozoa is proved because after coitus in rabbits 

 the blood of the female develops a specific ferment directed against spermatozoa. 

 (Waldstein and Eckler, "Der Nachweis resorbieiten Spermas im weiblichen 

 Organismus," Wien klin. Woch., vol. xxvi., 1913.) The term "Xenia," which 

 means guestgifts (see Thomson, Heredity, London, 1920), was applied by 

 Focke to cases of plants in which the male pollen was supposed to affect the 

 ovarian tissue (the seed's substance or the fruit) rather than the embryo itself. 

 The term has also been applied to cases of birds where the colour of the egg 

 laid is said to be influenced by the cock. Thus canaries crossed by siskins, 

 linnets, or goldfinches are described by Tschermak (Biol. Centralbl., 1910) as 

 having the colour of the egg-shells modified by the male which fertilised the ova. 



7 Stockard and Papanicolaou, "Hereditary Transmission of Degeneracy and 

 Deformities by Descendants of Alcoholised Mammals," Amer. Naturalist, 

 vol. 1., 1916, and Interstate Med.Jour., vol. xxiii., 1916. 



8 Pearl, "On the Effect of Continued Administration of certain Poisons to 

 the Domestic Fowl, etc.," Proc. Amer. Phil. Soc., vol. lv., 1916. 



