63 



bred, and again this foal was quite free from any zebra 

 infection. 



The conclusion that one must draw from these results is, 

 that so far no support is afforded to the telegony theory. 



In support of the idea that the stripes are due to rever- 

 sion to an ancestral form of the horse, it may be noted that 

 in several of the cases the foals were the result of union of 

 parents of widely different strains or races. This was so in 

 the case of the striped foal bred by Darwin ; and in that 

 bred by Professor Ewart from the West Highland pony by 

 an Arab sire ; and also to a less extent in that from the 

 same mare by an Island of Rum pony. Again, this was the 

 case in the foal from the New Forest pony by an Arab sire. 

 Now it is well known that the crossing of very distinct 

 races of pigeons tends to reversion to the ancestral blue 

 rock. Professor Ewart crossed pigeons of the owl and 

 Archangel breeds, and the result was more like the owl 

 parent than the Archangel. This owl-Archangel cross was 

 mated with a white fan-tail cock, and two young birds were 

 bred which, in colour, form, and movements, showed almost 

 complete reversion to the blue rock pigeon. A similar result 

 follows similar crossing of certain breeds of domestic fowls ; 

 a bantam hen was mated with an Indian game — Dorking 

 cock, and a cockerel was produced, almost identical with 

 the jungle fowl, believed to be the ancestral stock. If, 

 therefore, crossing of dissimilar races causes reversion, then 

 we must conclude that the striping of these foals may be 

 due to this cause, rather than to telegony. 



There was no crossing of dissimilar races, however, in the 

 case of the first foal borne by the Shetland mare mentioned 

 above. 



Professor Ewart considers that his experiments show that 

 telegony, if it occurs at all, occurs but seldom ; and in this 

 view he is in accord with the opinions of mule breeders on 

 the Continent. 



He adds that, should he find that out of about fifty pure- 

 bred foals, from mares which have previously produced 

 zebra hybrids, there is no undisputed case of infection, then 

 telegony must be discredited, at any rate, as being of any 

 importance to breeders of horses. 



Further experiments are certainly necessary, and bio- 

 logists will await with interest an account from Professor 

 Ewart of more " Penycuik Experiments." 



There is another subject that will probably prove of great 

 practical importance on which a good deal has been written 



