PREFACE 



THE favorable reception of the first edition of this 

 work by both press and public and my desire 

 to encourage the study of Veterinary Science and 

 Comparative Anatomy are the chief reasons for a 

 Revised Edition. The improvements consist in an 

 Ai^pendix, numerous Illustrations, a new Index, and 

 the correction of errors in and the addition of fresh 

 matter to the text and vocabulary. 



I am indebted to Mr. Jacob L. Wortman of Phil- 

 adelphia for the able article on fossil horses in the 

 Appendix, and to Prof. E. D. Cope, editor of The 

 American Naturalist^ for a careful revision and im- 

 provement of it. Some of the reference notes, how- 

 ever, are my own. 



It was not my intention originally to make the book 

 an exponent of the Doctrine of Evolution. The dis- 

 cussion of the subject, however, is justifiable, for a 

 work that does not embrace all the. facts science 

 furnishes is unworthy of the age, and to shirk the re- 

 sponsibility of the discussion because the subject is 

 unpopular is cowardly. The fact that fossil horses' 

 teeth are inseparably connected with those of the 

 modern horse renders their consideration unavoidable. 

 Further, in addition to being one of the most impor- 

 tant factors Paleontology has thus far furnished in 



