SYSTEM USED TN UFiEEDIKG CUIXEA-PIGS AND RABBITS. 307 



own experience goes, these requirements are best met by a sys- 

 tem similar to that described some years ago by Dr. Pearl and 

 myself^ for use with poultry. jNIethods involving the same 

 fundamental principles have also been described by Cole" for 

 use in pigeon breeding. 



Marking the Animals. 



The chief factor in establishing a reliable pedigree system 

 is to mark the animals in such a way that there is no danger of 

 mistaking them. About two years ago I corresponded with a 

 number of breeders and laboratories using small mammals in 

 an attempt to find what means were used for marking these 

 animals. For physiological experiments it seemed to be almost 

 universal to rely upon a description of color markings or in the 

 case of solid color animals to mark them with spots of various 

 anilin dyes. These together with cage records constitute the 

 chief means of distinguishing the animals. A number of ex- 

 perimental breeders rely ujDon various combinations of punch 

 marks in the ears to distinguish individuals. 



None of these systems is satisfactory. Color markings, 

 even conceding that tw^o animals are not marked alike, require 

 a considerable amount of time to compare the marks of the 

 animal with the description. Any system of ear punches or 

 anilin spots necessitates access to a key and again requires time 

 and energy to decipher their meaning. Further, the combina- 

 tions of punches and spots are quite limited so that it is very 

 difficult to run a continuous series for any considerable number 

 of individuals, l^esides, dyes are not permanent and the ears 

 are likely to be torn or pierced in fighting and so give trouble 

 m reading the numbers. 



Undoubtedly the most satisfactory method is to have a metal 

 tag or band bearing a stamped number, in which case there can 



-Pearl, Raymond, and Surface, F. M. — Appliances and ^Methods for 

 Pedigree Poultry Breeding, Maine Agricultural Experiment Station, 

 Bulletin Xo. 159, pp. 239-275. 1908, €f., also Zeit. f. Biol. Tech. u :\Iethod 

 Bd. I, pp. 285-295, 1909. 



^Cole. Leon J. — Methods of Keeping Pedigree Records in use at the 

 Rhode Island Agricultural Experiment Station. Ann. Rpt. R. I. Exper. 

 Station, 1908, pp. 317-324. 



