PRINCIPLES OF BREEDING 



A TREATISE ON THREMMATOLOGY 



OR 



THE PRINCIPLES AND PRACTICES INVOLVED IN THE 

 ECONOMIC IMPROVEMENT OF DOMESTI- 

 CATED ANIMALS AND PLANTS 



BY 



E. DAVENPORT, M.AGR, LL.D. 



PROFESSOR OF THREMMATOLOGY IN THE UNIVERSITY OF ILLINOIS 



DEAN OF THE COLLEGE OF AGRICULTURE 

 DIRECTOR OF THE AGRICULTURAL EXPERIMENT STATION 



WITH APPENDIX 



BY 



H. L. RIETZ, PH.D. 



ASSISTANT PROFESSOR OF MATHEMATICS IN THE UNIVERSITY OF ILLINOIS 



GIN-N.& COMPANY 



BOSTON . NEW YORK CHICAGO LONDON 



