602 



GENETICS IN RELATION TO AGRICULTURE 



Marking Individuals. The problem of marking individuals often is 

 difficult where large numbers of individuals are involved. When very 

 small herds are kept in which the animals may be known individually 

 this matter is not very important, because the animals may simply be 

 given a distinctive name, and any notes which it may be necessary to 

 make may be recorded under that name. But when individuals become 

 more numerous, it is usually necessary to have some safe and effective 

 way of distinguishing them. For cattle aluminum' ear tags of various 

 kinds are often used, and these may be obtained stamped with any numbers 

 which are desired. These may be used for smaller animals, also, or the 

 ears may be punched in various fashions. A method used by Dr. 



Fio. 234. Method of identifying sheep by holes punched in the ears. 



of Heredity.) 



(From the Journal 



Bell in sheep breeding experiments is illustrated in Fig. 234. By the use 

 of eight holes with place values such as are indicated in the diagram, it 

 is possible to identify 256 sheep according to the following combinations : 



Total sheep.identified by hole 1 



Total sheep identified by 1 hole 8 



Total sheep identified by 2 holes 28 



Total sheep identified by 3 holes 56 



Total sheep identified by 4 holes 70 



Total sheep identified by 5 holes 56 



Total sheep identified by 6 holes 28 



Total sheep identified by 7 holes 8 



Total sheep identified by 8 holes 1 



This is a very simple mode of identification, and by means of a rubber 

 stamp with a sheep's head outline or description sheets having such 

 a head as that shown in Fig. 234 printed upon them, it is very easy to 

 record accurately the designation which has been given to any particular 

 sheep. The method can of course be used with other animals, and it 

 avoids the difficulty of loss which sometimes is met with in using ear tags. 



