CARDINAL AND ACCESSORY RESPIRATION 563 



not be mistaken! This is not to say that this is actually 

 the case ; but the author believes that it is possibly true. 



TISSUE RESPIRATION 



In the failure of the oxidases and catalases to fulfil the 

 hopes that were rested upon them, we have endeavored 

 in other lines to approach the problem of the combustion 

 processes of the living body. 



Cardinal Respiration and Accessory Respiration. In 

 the first place the systematic studies of F. Battelli and L. 

 Stern should receive attention. These authors make a dif- 

 ferentiation between the cardinal respiration and the acces- 

 sory respiration of animal tissues. The former is by far 

 the more important, although, too, much the more labile 

 process, and involves the life of the cells. In many tissues 

 (especially richly in muscles) there is an agent of unknown 

 nature, "pnein," which is capable of increasing the cardinal 

 respiration of the tissue as this becomes progressively 

 weaker after the death of the animal. By washing out the 

 " pnein" for the most part the tissues thus freed manifest a 

 very low respiratory activity, but by introduction of pnein 

 this can be very distinctly increased. The pnein is looked 

 upon as an "activator of the fundamental respiratory 

 process, " but has no influence upon the accessory respira- 

 tion. It is apparently a substance resistive to boiling tem- 

 perature, to pepsin and trypsin ; soluble in water and dialy- 

 sable, slightly soluble in alcohol, insoluble in ether. In va- 

 rious animal tissues there is also an agent which decreases 

 the cardinal respiration ; it is known as "antipneumin.** 



While the cardinal respiration is not dependent upon 

 agencies of ferment type, apparently the accessory respira- 

 tion is. The intake of oxygen in the latter is not under all 

 conditions accompanied by the formation of carbonic acid. 

 While the cardinal respiration, as stated, is of very labile 

 nature, the accessory respiration may remain unchanged in 

 tissues for twenty-four hours or more. If a tissue is finely 



