i26 SCIENCE PROGRESS 



within the last few years. He studied the changes taking place 

 in green maize stems packed closely together to form a "silo." 

 Bacterial action sets in, and also action of the respiratory 

 oxidases and other enzymes of the plant cells. So large an 

 amount of heat is generated by the oxidases that the tempera- 

 ture rises to such a degree as to inhibit further bacterial growth. 

 The hydrolytic and proteolytic enzymes still retain their activity, 

 however, and a complicated series of changes ensues, in which 

 organic acids appear among the products. 



In the foregoing account of the oxidases the chief difficulty 

 experienced by the author has been that of deciding what to 

 omit, as the subject is of such dimensions and of such rapid 

 growth. Furthermore it has not been possible to present both 

 sides of all the questions involved, owing to limitation of 

 space and a desire to give a connected account of the various 

 researches. 



