PREFACE. 



The author has for years given attention to the dis- 

 eases encountered in the poultry -yard, and long since 

 became impressed with the desirabilit\' of a sys- 

 tematic treatise on the subject. The pamphlets, by 

 various authors, which have appeared in the English 

 language have been very useful, but they have been 

 far too brief, they have not contained the results of 

 modern investigations and the}' have lacked illustra- 

 tions. There have been more extensive monographs 

 in German, French and Italian, but these have been, 

 for the most part, sealed books to English-speaking 

 poultry men. 



It has been necessary for the author to examine 

 much of the literature of this subject in order to keep 

 abreast with the progress of science and to reply in- 

 telligently to the numerous inquiries which he has 

 received. The notes thus made led to the writing of 

 a number of articles for the press, which were so well 

 received and brought out so many requests for more 

 information, that it was decided to fill in the parts 

 which had not been touched upon and produce a small 

 reference book for the use of those interested in the 

 subject. This volume is the result, and it is hoped 

 that it may prove useful to the thousands who are an- 

 nually under the necessity of struggling with the 

 problem of disease in the poultry -yard. 



The author has, in the preparation of this work, 

 consulted with much profit the Medccine des oiseaiix. 



