THE CROSSING, AC, OF PIGS. 295 



flies, if possessed of all the characters of its species, is, 

 to the full, as perfect, physiologically, as the elephant, 

 which is of such complex development 



The principle before referred to, respecting the im- 

 possibility of an ill -proportioned breed, long continu- 

 ing its existence, without crossing, or otherwise chang- 

 ing its form, is strikingly displayed in the case of the 

 Pig, whose breeds are, under domestication, all ill-pro- 

 portioned. To ward off the extinction of the highly- 

 bred breeds of Pigs, crossing has to be resorted to, all 

 the time. In one of the quotations, above given, it is 

 seen that Darwin deems it worthy of note, that a Mr. 

 Fisher Hobbes, by means of "judicious selection," and 

 by " dividing his stock into three separate families," 

 "maintained the breed for more than twenty (!) years." 



In this connection, Darwin says (p. 240, Vol. ii, 

 Animals and Plants, &c.) : 



"Our Pigs, as Mr. Carrington remarks, during the 

 last twenty years, have undergone, through rigorous 

 selection, together with crossing, a complete metamor- 

 phosis!" 



And again, in noting the many breeds, of all species, 

 which " have become extinct," he says : * * * 



"At the present time, improved breeds sometimes 

 displace, at an extraordinarily rapid rate, older breeds ; 

 as has recently occurred throughout England, with 

 Pigs." 



All of the present, cultivated breeds of Pigs, have 

 been produced by crossing. When crossed, the animals 

 start off with a stock of characters, derived from the 

 two old breeds ; which enables them to run for awhile, 



