102 BOARD OF AGRICULTURE. 



extinct, and at once restored the fertility by a cross with an 

 Essex boar. Mr. J. Wright bred from a boar and its daughter, 

 grand-daughter and great-grand-daughter, and so on, through 

 seven generations. The offspring in many instances failed to 

 breed, in others they were mostly too weak to live, and those 

 that did survive were unable to walk steadily or even to suck 

 without assistance, The two last sows obtained in this way 

 produced several litters of fine healthy pigs, though one of them 

 at least had been previously served by her own sire without suc- 

 cess. This sow was the best formed of the entire race, but there 

 was no other pig in the litter. This case is remarkable, as show- 

 ing a steady improvement in form and symmetry, advancing side 

 by side with a steadily increasing weakness of the constitution, 

 and of the mental and reproductive powers. Nathusius imported 

 a pregnant Yorkshire sow and bred the progeny closely in and 

 in for three generations, with the effect of seriously impairing 

 the constitution and fertility. One of the last of the pure race, 

 when bred to her own uncle, who was quite prolific with other 

 breeds, had a litter of six, and on a second trial, one of five 

 weakly pigs. He then had her served by an imported black 

 English boar (which got litters of from seven to nine with his 

 own breeds), and got a first litter of 21 and a second of 18. 



The Sebright bantams closely bred were very barren, and this 

 tendency in fowls is remarked by Wright, Clark, Eyton, Hewitt, 

 Ballam, Tegetmeier and others. 



But it will be observed that these evil results accrue from a 

 persistent breeding from the very closest affinities. Experience 

 has shown, in the case of our high-bred cattle and sheep, that 

 constitution and fertility may be preserved without sacrificing 

 the breed by introducing inferior blood. The true course, in 

 case these evil results are threatened, is to select a male of the 

 same general family, but which has been bred apart in a sub or 

 branch family for several generations, and if attainable, from a 

 different locality, climate and soil. Constitution and fecundity 

 may thus be improved without even a temporary deterioration 

 in other respects. 



ll^A. Disease and Accident. — That disease, or changes the re- 

 sult of disease or of accident, are inherited among domestic 

 animals, there cannot be the slightest doubt. Simple changes of 

 structure from accidental causes are less frequently perpetuated 



