FARM AXIMALS. 37 



The heredity of normal characters means the transmis- 

 sion of those characters which are natural to the type. 

 These may be original traits bestowed upon the species, 

 as for instance, timidity in sheep; or they may have been 

 acquired and rendered permanent by long-continued trans- 

 mission, as in the changed form of all the improved breeds 

 of domestic animals. The heredity of abnormal characters 

 means the transmission of irregular characters, or those 

 which have deviated from the natural and acquired char- 

 acteristics of the type. These abnormal characters may 

 appear as malformations of structure, derangement of 

 function, or they may assume one or the other of various 

 forms of disease. Illustrations of the first are found in 

 certain families with an irregular number of fingers and 

 toes; of the second in the inheritance of deafness, dumb- 

 ness and impaired vision; and of the third, in the reap- 

 pearance in the offspring of certain diseases possessed by 

 the parents, as, for instance, any of the forms of scrofula 



The laws which govern heredity are those also which 

 determine the results in practical breeding. In practice 

 the rules which govern it are almost entirely empirical in 

 their origin, since they have been almost exclusively de- 

 rived from the accepted methods of the most successful 

 breeders. Those who have given thought to the question 

 will concede that breeding live-stock is at once a science 

 and an art. They will see in it a science in so far as it 

 discovers and systematically arranges those truths and 

 principles which relate to the improvement of live-stock, 

 and it will appear to them an art in so far as they perceive 

 that those principles can be successfully utilized in prac- 

 tice. It is apparent therefore that the relation between the 

 science and the art of breeding is both close and intimate. 

 Without some knowlege of the former the latter is not 

 likely to be successfully practised, and the measure of 

 success which attends the efforts of the breeder will be 

 largely proportionate to the measure of the knowledge 

 which he may possess of the principles of heredity. 



Reference has been made to certain laws which govern 

 transmission. Of these three may be considered as funda- 



