General Discussion 57 



The equation of Puetter corresponds to the known sigmoid survival rate 

 in man. 



Tliere are two different ageing processes: one shoAvs a decline from 

 birth to death, the other is characterized by an up and down of develop- 

 ment (youth, maturity and senescence). 



There is no strict parallelism between the changes of the different 

 organs of the organism, nor their parts. This is true for physical and 

 mental faculties. 



Life shows different levels of vitality (tonus) which are characterized 

 by the ease with which an individual holds its ground physically and 

 mentally. The higher the level of vitality, the better the organism is 

 capable of withstanding injuries and even over-strain. 



Not mere longevity is the aim, but the maintaining of a level of vitality 

 as high as possible even in the declining phase of life. 



Verzdr: I wonder whether Dr. Miescher would be willing to change his 

 first sentence so that the last word is not "vitality" but "adaptab lity". 

 I could agree to the definition then. 



Miescher: I think that the concept of vitality is the broader one, 

 embracing adaptability. Besides, vitality has two aspects, a physical 

 and a psychological one. 



Verzdr: I think adaptability is the elasticity of tissues or the com- 

 pensatory hypertrophy of organs, or might be the adaptability to 

 different physical changes, atmospheric and other conditions, and even 

 to new psychological situations. 



Miescher: In any case different levels of vitality or adaptability have 

 to be considered. 



Tunbridge: But you are not wanting the man of sixty to be the man 

 of twenty. You are accepting the fact that there might be standards of 

 decline? There is not very much difference between you: Dr. Miescher 

 is saying he wants 100 per cent vitality of the standard for the age, 

 which I think Prof. Verzar would accept as adaptability to the highest 

 function for that age. 



Miescher: In fact it is simply a question of definition. 



