PREFACE TO SECOND EDITION. 



IN this second edition, the results of last year's earnest 

 work have been embodied. The efforts of Bacteriologists, 

 since Koch's tuberculin announcement, have been directed 

 to the elaboration of therapeutic agents from the chemical 

 products of Bacteria. Physiological chemistry can accom- 

 plish more here than Bacteriology. The separation from 

 the blood of Antitoxines, and their application to the cure of 

 disease, will probably revolutionize our present method of 

 treatment, and add some peculiar agents to our Materia 

 Medica. The question of immunity is still unanswered, 

 though the Phagocytic theory of Metschnikoff and the 

 Alexines of Buchner are bringing us to the solution. Upon 

 these lines the greatest efforts are at present being made. 



We are very grateful to all those who have taken notice 

 of our little effort, and we hope to merit a continuance of 

 their regard. 



The way in which the first edition was received assured 

 us of its success. 



M. y. B. 



