CHAPTER XII. 

 NON-FERTILITY AND LACTATION IN MULES. 



The natural history of hybrids of all kinds has not received 

 due consideration even from naturalists and scientific 

 observers, and but little is known regarding them compared 

 with what has been ascertained respecting their progenitors. 

 No careful consideration of the facts relating to hybrids 

 has been put upon record, a few scattered observations as 

 to the fertility of some, and the absolute sterility of others, 

 are about all that has been made known. 



The extraordinary circumstance that Mr. Bartlett, 

 superintendent of the Grardens of the Zoological Society, 

 should have definitely ascertained that fertile hybrids can 

 be bred between species as distinct as the bison of North 

 America, the buffalo of India, and the wild ox of Europe, 

 has passed almost unnoticed, although portraits of the 

 singular triple crosses so produced have been published 

 in the Proceedings of the Society. But no further 

 experiments have been made with the view of introducing 

 either of these crosses into our breeds of domestic 

 cattle, with the possibility of improving the characters of 

 the latter, and at present the only advantage that has 

 been gained by Mr. Bartlett's interesting experiments has 

 been to ascertain the fact that three very distinct species 

 of the Bovida3, inhabiting different parts of the world, can 



