PREFACE 
TO THE SECOND EDITION. 
In the preparation of this second edition it has 
been the intention of the author to bring the subject 
matter abreast of the many advances made in the last 
few years, but not to change the arrangement of the 
book. In order to do this many of the chapters have 
been rewritten. In the chapter on Immunity the prin¬ 
ciples of complement fixation have been added in as 
simple a way as it is possible to do with a complex and 
rather confusing subject. 
Harry W. Carey, A.B., M.D. 
Troy, N. Y. 
(HO 
