Preface. y 



In the list of contagious diseases are included not only 

 those that are habitually developed on American soil and 

 those already introduced from abroad, but also such as 

 prevail in Europe, and are liable at any time to be brought 

 into our midst by importation. It is no less imperative 

 that the American farmer should be forewarned of pesti- 

 lences that threaten him from abroad, than of those that 

 beset him at home. For all such affections the principles 

 that should guide us in preventing and extinguishing the 

 disease are concisely but clearly set forth. 



All the important parasites are introduced and their 

 conditions of life and individual metamorphoses in and 

 out of the bodies of domestic animals referred to, as well 

 as their migrations from man to animals and from animals 

 to man wherever such exists. The vast importance of 

 animal parasites is only beginning to be realized ia con- 

 nection with their frightful ravages in countries (England, 

 Australia, Buenos Ayres, Egypt, Abyssinia, Iceland, India, 

 etc.,) into which they have been introduced or where they 

 have been allowed to increase unchecked, and a concise 

 statement of their forms, habits and results is therefore 

 imperatively necessary for the protection of the stock 

 owner. This subject has accordingly been brought up to 

 the date of present observations, and though short enough 

 for the perusal of the busiest it wiU furnish a sound basis 

 for the Umitation and destruction of each of these noxious 



p'jsts. 



JAMES LAW, 



Cornell Univer^ty. 



Ithaoa, May, 1876. 



