306 MAINE AGRICULTURAL EXPERIMENT STATION. IQI3. 



II. A PEDIGREE SYSTEM FOR USE IN BREEDING 

 GUINEA-PIGS AND RABBITS.^ 



By Frank M. Surface. 



For use in experimental breeding an adequate yet simple 

 method of recording pedigrees is indispensable. Further, to 

 one who has once used pedigreed material for physiological ex- 

 periments the advantages of such material are very evident. In 

 many of the delicate biological reactions for which small 

 mammals are extensively used it is often clearly evident that 

 all animals do not react alike. In many cases it can be sup- 

 posed that such idiosyncrasies are a matter of heredity. Accu- 

 rately pedigreed material will often aid in solving otherwise 

 very puzzling results. On the other hand, experimental breed- 

 ing is just beginning to recognize the heritability of physiologi- 

 cal characters. The keeping of accurate records for a period 

 of time will undoubtedly throw much light upon this phase of 

 heredity. 



With this two-fold object in view the writer recently devised 

 a system of pedigree and other records for use with small 

 mammals. These records have been in use for a number of 

 months and their adequacy and simplicity have been clearly 

 demonstrated. It seems not unlikely that a description of 

 these methods may be of interest to investigators in several 

 fields. 



The chief requirements of any pedigree system are (i^ 

 accuracy, anid (2) simplicity. This simplicity should include a 

 minimum of operations in recording an animal and an easy ac- 

 cessibility to all the data for any individlial. So far as my 



'Papers from the Biological Laboratory of the Maine Agricultural Ex- 

 periment Station, No. 58. 



The experiments reported in this paper were carried out while the 

 writer was connected with the Kentucky Agricuhural Experiment Sta- 

 tion. 



