VI. OXIDATION AND IMMUNITY 



ACCORDING to the view which was formerly generally 

 accepted, animal oxidations occurred in the fluids 

 of the organism. To-day, led by Pfliiger and other 

 investigators, we believe that oxidation occurs in 

 the tissues, and with formed elements. How oxida- 

 tion occurs is not a settled point, but it may be 

 viewed from the ionic standpoint. 



A body which is oxidised by neutral oxygen at 

 the temperature of that body is said to be easily 

 oxidisable or auto-oxidisable. On the other hand, 

 bodies which are indifferent or nearly indifferent to 

 neutral oxygen, as the proteids, fats, and carbo- 

 hydrates, are not auto-oxidisable, but are said to be 

 dys-oxidisable or brad-oxidisable substances. How 

 do such oxidations take place ? In auto-oxidation 

 a cleavage of the neutral oxygen into ions occurs. 

 The auto-oxidisable substance combines with one of 

 the oxygen ions, while the other is free to oxidise 

 dys- or brad-oxidisable substances which may be 

 present at the same time. The latter is called a 

 secondary oxidation. 



Living protoplasm has a peculiar construction de- 

 pendent upon the special construction of its proteins. 

 These are called living or active proteids or biogens ; 

 and they differ from non-living proteid, such as is 



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