PREFACE, 
My object in writing this book is simply to indicate 
that there is a natural history of disease, as well as of 
plants and animals. I have not attempted to deal with 
the subject at great length, far less exhaustively, but 
merely to illustrate general principles by a few carefully 
selected examples. 
The subject is a novel one, and doubtless a more 
extended study will serve to show that many of my 
conclusions are fallacious. I trust that such errors may 
be speedily rectified by any person who has opportu- 
nities of testing my opinions practically. It must be 
borne in mind that it is a much easier task to write 
concerning the habits of animals than to describe their 
diseases ; nevertheless, the facts at our disposal clearly 
indicate that disease is controlled by the same laws 
which regulate biological processes in general. 
J. B.S. 
