vi PREFACE 



Obviously, licentiates to practice medicine should re- 

 ceive instruction of a definite and practical nature in 

 this important branch of modern medicine, or immu- 

 nology should receive a place in the classification of 

 specialties, a fact which the importance of the subject 

 may command. 



In this book it has been the aim of the authors 

 purposely to omit most of the experimental research 

 and to present theories only in so far as they may 

 assist in a more thorough comprehension of biological 

 prophylaxis, diagnosis and therapeusis. 



The primary object has been to crystallize and de- 

 tail the practical phases of serum and bacterin applica- 

 tions in medicine, thereby enabling the student and 

 general practitioner, with even a slight laboratory ex- 

 perience, to appreciate the significance of, and more 

 competently apply the principles underlying, immu- 

 nology. In order to render the treatise more complete 

 allusion has been made in places to certain allied sub- 

 stances that have been utilized from time to time in 

 attempts at immunization, with a consideration of 

 their merits and demerits. 



The interest and close association of blood trans- 

 fusion, organotherapy and administration of salvarsan 

 and neosalvarsan to the main subject have prompted 

 the authors to devote an appendix to their discussion. 



The reader who may have his enthusiasm aroused 



