PREFACE. 



This Essay is based on a series of experiments which were 

 instituted by the author in consequence of the sudden ap- 

 appearance of a mahgnant exanthematous disease in the 

 flocks of several agriculturists in the vicinity of London, and 

 which seemingly depended on the sheep being mixed with 

 some imported " merinos." An examination shewed that the 

 malady possessed many of the features of human variola, and 

 was, in fact, the small-pox of sheep. 



Originally the author intended to have placed the matter 

 before the veterinary profession in particular in a series of 

 papers in the "Veterinary Record;" but, finding that the dis- 

 ease rapidly extended, he resolved to bring his researches 

 into its nature and treatment before the public in the form 

 of a pamphlet. And he would fain indulge the hope that, in 

 taking this course, he may be instrumental in benefitting the 

 agricultural commimity, whose flocks are in danger of being 

 decimated by a scourge which previously had confined its 

 ravages to the continent. The work has been v* ritten during 

 the intervals of professional avocations, combined with the deli- 

 very of a sessional course of instruction, and the author is well 

 aware of its many imperfections ; yet he hopes it will be 

 found to contain at least an outline of what is known on the 

 subject. He could have wished that the task had devolved 

 on one more capable of doing it justice ; but, considering the 

 situation A\hich he has the honour to hold, namely, the 

 Lectureship on the Anatomy and Diseases of Cattle at the 

 Roval Veterinary College, he felt that it was a dutv from 



