Preface to the Second Edition. 



THOUGH scarcely a year has elapsed since the 

 publication of the First Edition, yet it has been 

 possible to widen the scope of the Second in many 

 points. Since then, numerous investigations in 

 different fields have been either begun or completed. 

 The most important results of these investigations 

 are given at the end of this little volume. 



The term " protective ferment ' has been dropped, 

 because it may easily convey the idea that these 

 ferments, which are called into action by the presence 

 of substances out of harmony with the plasma, are 

 unconditionally protective. The term " defensive 

 ferment will more readily suggest the notion, that 

 the animal organism attempts to defend itself. By 

 means of decomposition it often deprives dishar- 

 monious substances of their specific character, but in 

 many cases the defensive ferments form decom- 

 position stages which are more dangerous than the 

 substrates they attack. 



May this new edition find the same friendly 

 welcome as the first. 



EMIL ABDERHALDEN. 



Halle a/S., 



June 15, 1913. 



