88 ZEBRAS, HORSES, AND HYBRIDS 



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 fur 

 Omithologie, 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 egg- 

 shell must be caused by some change brought about 

 in this gland by cross-fertilization, we begin to recog- 

 nize how mysterious and inexplicable are many of the 

 problems which affect breeding. 



Throughout his account of his experiments Pro- 

 fessor 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 ex- 

 periments, as far as they have gone, afford no evidence 



