76 THE EVOLUTION OF DEATH 



A similar criticism may be directed against the current 

 medical theory of growing old which seeks to explain the 

 observed weaknesses and difficulties of old men by the 

 condition of their blood-vessels, especially of their arteries. 

 Thus Osier has said a man is as old as his arteries. This view 

 rests upon clinical experiments, for in fact the disturbances 

 in the case of senile weakness, which are occasioned by the 

 altered structure of the walls of the vessels, are especially 

 noticeable and yield valuable symptoms for the diagnostician. 

 We have, however, to do with the consequences, not with the 

 causes, of senility. 



Professor Miihlmann has also written repeatedly concerning 

 extreme old age and his memoirs contain many interesting 

 and valuable statements. He offers us also an explanation 

 of senility. The latest memoir of Miihlmann^^ of which I 

 know, and which must be here considered, appeared in the 

 year 19 10. In it he discusses my theory. The present 

 opportunity does not appear to me suited to discuss Miihl- 

 mann's critic fully and to answer it. Permit me to direct 

 your attention to it, because quiet discussion leads to the 

 settlement of scientific problems. I venture to add that 

 I am still convinced that my view can be successfully defended 

 against Miihlmann's attack. Miihlmann writes, strictly 

 speaking, from the medical point of view, or in other words 

 from an anthropomorphic point of view. He is concerned. 

 with rendering the phenomena in man more comprehensible 

 without having regard to the corresponding phenomena as 

 they occur in living organisms in general. Investigations 

 which are conducted by such thoughts as we know from 

 experience lead to valuable results. They can, however, 

 only exceptionally bring forth results which are com- 

 pletely satisfying to biologists. Miihlmann attributes 



