10 Preface to Ninth Edition 



tions included in the present volume. He is especially indebted to 

 members of the animal husbandry and dairy husbandry divisions of 

 the University of Minnesota for advice and help, particularly to 

 Professor E. F. Ferrin for assistance in revising discussions of the types 

 of hogs. For special information and data which they have furnished 

 upon various subjects, the writer is indebted to E. W. Sheets, acting 

 chief of the animal husbandry division, U. S. Bureau of Animal Indus- 

 try; C. V. Whalin, in charge, marketing live stock, meats, and wool 

 division, U. S. Bureau of Agricultural Economics; J. S. Montgomery, 

 manager of the Central Cooperative Commission Association, St. Paul, 

 Minn.; R. A. Hammond, manager, Ohio Sheep and Wool Grow- 

 ers' Association, Columbus, Ohio; Edward N. Wentworth, director. 

 Armour's Livestock Bureau, Chicago, 111.; and L. D. H. Weld, manager. 

 Commercial Research Department, Swift and Company, Chicago, 111. 

 Many of the illustrations which appear in the following pages have 

 been kindly supplied by authors of experiment station and other pub- 

 lications, teachers, breeders, breed record associations, and others. 

 Individual mention of these is made in the list of illustrations, beginning 

 on page 13. In this list credit is also given for illustrations which 

 originally appeared in other publications and which are reproduced 

 herein with the permission of the authors or publishers. 



St. Paul, Minnesota H. W. VAUGHAN 



July, 1923 



