14 BULLETIN 905, U. S. DEPARTMENT OF AGRICULTURE. 



Thus in many respects the breeder should act much as if acquired 

 characteristics were inherited. On the other hand, it is important to 

 know that it is hopeless to attempt to improve scrub stock merely by 

 giving it the best of care for any number of generations. 



Probably the strongest reason for the common belief in the inherit- 

 ance of acquired characteristics is that to many it seems impossible 

 to account for progress in any other way. To this it may be said that 

 while the hereditary qualities of the reproductive cells do not seem 

 to be influenced by changes in the individual, they are not unchange- 

 able. Variations occur from time to time, apparently at random. 

 By the methods discussed later these variations may be combined 

 in desirable ways and fixed in a stock. 



TELEGONY. 



It was widely believed at one time that after a female has borne 

 young, sired by a certain male, her later offspring, sired by other 

 males, will show characteristics derived from the first — a supposed 

 phenomenon which has been called telegony. Such an influence 

 could come only from a modification of the egg cells of the female by 

 influences from the first offspring before birth, and so come under the 

 head of the inheritance of acquired characteristics. It is even more 

 improbable, however, as the influence of the first male must neces- 

 sarily be very indirect. The most widely quoted example of this 

 sort of influence was a case in which a mare was mated with a zebra, 

 producing a hybrid, and later, after mating with a horse, produced 

 a colt which had certain markings which resembled those of a zebra. 

 This, however, was merely an isolated case. A considerable number 

 of attempts have been made to confirm it, but with no success. The 

 most extensive experiments were those of J. Cossar Ewart, likewise 

 with zebras and mares. He could find no effects which could be 

 ascribed to telegony. There was, indeed, one case in which a mare 

 produced a colt with vestiges of stripes after having produced a 

 hybrid. It was found, however, that the sire of this colt, an Arab, 

 produced similarly striped colts from mares which had never seen a 

 zebra. 



Similar experiments with zebra crosses, also with negative results, 

 have been carried on by the Bureau of Animal Industry. F. B. 

 Mumford and C. B. Hutchinson made an investigation of the ques- 

 tion in the mule-breeding district of Missouri. Many cases were 

 found in which mares bore mule and horse colts successively, but no 

 evidence could be found for telegony. The theory is now considered 

 to be thoroughly discredited and is evidently one which need give 

 the practical breeder no concern. 



