PEEFACE 



No apology appears necessary for the increase in size of 

 this Edition; it was impossible within any smaller compass 

 to deal with a subject of the first importance. The time 

 had arrived when the whole question required more exten- 

 sive handling than was considered desirable when the first 

 edition of this book was published; in consequence the 

 Manual has been completely rewritten. 



The extraordinary advances made in our knowledge 

 during the last eighteen years have revolutionized our 

 pathology, and an accurate knowledge of pathology is one 

 of the pillars of preventive medicine. 



It was impossible that a work organized on the present 

 lines could be carried out single-handed. I have been 

 fortunate in securing the co-operation of Dr. Arnold 

 Theiler, Veterinary Pathologist to the Government of the 

 Transvaal, in writing the chapter dealing with Bacteria 

 and Immunity. I am indebted to his original investiga- 

 tions, and those of Mr. Lounsbury, B.Sc, Entomologist to 

 the Government of the Cape of Good Hope, in the matter 

 of the Tick transmission of disease. The profound influence 

 which the work of these gentlemen has exercised over our 

 knowledge of the infection and prevention of tropical 

 diseases of animals cannot yet be fully estimated. As a 



Digitized by Microsoft® 



