398 COLLECTED STUDIES IN IMMUNITY 



phenomena of metabolism, while they are also at the same time the 

 two phases of the vital process. 



" As a result of a large number of facts we have, as is well known r 

 arrived at the conclusion, confirmed chiefly by Pfluger, that the mid- 

 point of metabolism is represented by complicated combinations of 

 egg albumin called by Pfliiger living albumin. Such combinations 

 are exceedingly labile, decomposing to a certain extent sponta- 

 neously, and to a greater degree in response to stimuli In these 

 combinations we are dealing with chemical substances whose mole- 

 cules, just because of this easy decomposition, disclose a chemical 

 constitution quite different from the lifeless albuminous bodies which 

 we know. I have therefore proposed to replace the name 'living 

 albumin molecule' by the term 'biogen molecule.' The decomposi- 

 tion and production of the biogens is therefore the corner-stone of the 

 vital process in every living cell. The substances given off by the 

 cell are derived from the decomposition of the biogens; the material 

 for the formation of new biogen molecules is furnished by the food 

 taken up and transformed by the cell. 1 have, however, called 

 attention to the fact that this view needs to be extended in one 

 direction (Allg. Pr^siologie, Jena, 1897). A number of facts indi- 

 cate that the decomposition of the biogen molecule is not complete 

 and that all of the atomic groups thus arising are not given off by 

 the cell." 



In view of these explanations Verworn assumes that in the de- 

 composition of the biogens a residue is always left which again 

 takes up food substances and so regenerates the biogen molecule. 

 It seems to have entirely escaped Verworn that I had expressed 

 entirely analogous views in much greater detail twelve years pre- 

 viously (" Uber den Sauerstoffbediirfniss des Organismus," Berlin, 

 1885). I assumed that the specific function of the cell is depen- 

 dent on a central group in the living protoplasm, of peculiar 

 structure; furthermore, that atoms and atomic groups are attached 

 to this central group as side-chains. These side-chains arc of subordi- 

 nate importance for the specific cell function, but not so for the life itself. 

 I also said that everything indicated that it was just through these 

 indifferent side-chains that physiological combustion was effected, 

 for one portion of these side-chains effects combustion by giving 

 off oxygen, the other portion being thus consumed. On page 11 of 

 this monograph I expressed myself as follows: "The question as 

 to the manner in which the side-chains constantly being consumed 



