38 Discussion 



Best: Dr. Comfort, you seemed to use the terms "vigour" and "life" 

 interchangeably at times. 



Comfort: As regards "vigour", I have used the term rather than 

 "longevity" and have used it, not in a strictly Darwinian sense, to mean 

 the whole group of characters which tend to enable an animal to stand 

 up to its environment. All animals either die from a cause that could kill 

 them at any age, and which is not really germane to ageing, or from a 

 cause which would not have killed them when they were more vigorous. 

 You can probably defend the interchangeable use of "longevity" and 

 "vigour" to that extent, unless you consider that "vigour" should only 

 be used to mean vigour in the sense of characters which are strictly 

 associated with Darwinian fitness. 



Best: We need superb clinicians for tadpoles and other lower organisms. 

 It is, of course, extremely difficult to decide even in human patients 

 whether or not premature ageing is complicated due to infections or 

 other definitely pathological processes. 



