THE CONDITION OF OLD AGE 25 



has noticed as a result of his meditations upon the 

 arrangements within our bodies that we suffer very 

 much from what he calls disharmonies, by which he 

 means imperfect adaptations of structures within us 

 to the performance of the body as a whole. He 

 mentions various instances of such disharmonious 

 parts. They do not seem to me quite so imposing 

 as apparently they do to him, for many of his dis- 

 harmonies are based upon the fact that we do not 

 know that a certain structure or part has any useful 

 r6le to play in the body. But I am inclined to sus- 

 pect that in many cases it is only because we are 

 ignorant ; the list of useless structures in the human 

 body was a few years ago very long ; it has within 

 recent years been greatly shortened, and we should 

 learn from this experience a caution in regard to 

 judging about these things, which, I think, Professor 

 Metchnikoff has failed to exert duly in forming his 

 opinions on these disharmonies. Now among the 

 disharmonies which he recognises is that of the great 

 size of the large intestine, which is of such a calibre 

 that a considerable quantity of partially digested food 

 can be retained in it at one time. When such food 

 is retained in the intestine, it may undergo a process 

 of fermentation. There are many sorts of fermenta- 

 tion, and some of them produce chemical bodies which 

 are injurious to the human organism. Bacteria, which 

 will cause fermentation of this sort, do actually occur 

 in the human intestine. Metchnikoff thinks that, as 

 we grow old, this tendency to fermentation increases. 



