PREFACE 



As stated on the title pag^this little book is 

 made up of the Herter Lectures given in 1916 

 at the University and Bellevue Medical School, 

 New York. These lectures were published in 

 the Journal of Laboratory and Clinical Medi- 

 cine. There has been some demand for re- 

 prints, of which none were made. I have, there- 

 fore, gladly acceded to the request of the pub- 

 lishers, The C. V. Mosby Company, who have 

 offered to present them in the present form. 

 The researches upon which they are founded 

 have occupied much of my time for many years, 

 and have given me a concept of the nature of 

 infection, quite different from that usually 

 taught. 



Hoping that, in this form, my studies may be 

 helpful to my fellow-workers in the profession, 

 I submit this booklet to them. 



THE AUTHOR. 



Ann Arbor, Mich., 1917. 



