88 Maine Agricultural Experiment Station. 1919. 



2. Starting at any point it is equally easy to go forward 

 or backward on a pedigree or to go into collateral branches. 

 This facility depends on two fundamental facts ; viz., (a) that 

 the individual mating is the natural unit in breeding operations, 

 and (b) that on the same sheet on which the record of any 

 individual appears there appears also the number of the mating 

 from which this individual originated on the one hand, and 

 the numbers of the matings in which it takes part on the other 

 hand. In other words, whether on mating sheet or in the des- 

 criptive catalog, the connection of the individual both with 

 what is behind and what is beyond in the pedigree is always 

 maintained. 



3. Owing to the fact that designating numbers of indi- 

 viduals do not in this system attempt to carry the pedigree with- 

 in themselves, there is no tendency for these numbers to be- 

 come complex. Complexity in designating numerals, and ac- 

 curacy in entering and extracting pedigree records are very 

 difficult things to have in common. 



4. The "system of pedigree records described is in effect 

 a double entry one. This feature makes for accuracy because 

 it makes it possible to detect errors which may get into the 

 records. 



5. The system is a very elastic one. By making very 

 slight changes in matters of detail it can be adapted to keeping 

 pedigree records in any kind of breeding work with either 

 plants or animals, or as has been pointed out by Galton (loc. 

 cit.) to keeping human family records. 



6. Most important of all is the simplicity of the system. 

 It is so simple and straightforward that once its essential fea- 

 tures are grasped it is only by gross carelessness that an error 

 in the records can be made. 



