General Discussion 25 



is of individuals or of cells. Now, as Prof. Medawar has pointed out, you 

 can't get a similar population of human beings because tlieir individual 

 Iieredity is all different and the races are different. We can standardize 

 the population as to age and sex, but that's all. As to the histological 

 changes, I'd like to mention the change in elastic tissue — ^you have all 

 done it, I know, it's an old trick: you pull up the skin on the back of the 

 hand, placed in a flaccid way on the table, and with an old person like 

 me it settles down with dignity, but if you take a young hand and do it, 

 it snaps back. There, ladies and gentlemen, is one of the best histo- 

 logical measurements of age. 



Vischer: Perhaps I may add a few points to the remarks Prof. Cameron 

 made about the two centenarians whom we were able to observe dm-ing 

 the last years of their life. First of all, their mental state was important. 

 As Prof. Cameron said, the old lady whose last years had been very 

 much troubled by the severe mental disease of her daughter, was 

 absolutely struck down by the death of this daughter. That shows that 

 the general assumption that old people lack feeling and affectivity was 

 not true in this case. The old man was in hospital in his hundredth year. 

 When he watched a Christmas play done by Scout girls his face grew 

 first red and then purple, and I feared an explosion. Afterwards he told 

 me that as a Darwinist and a Calvinist he was very much scandalized by 

 this play, which was against his principles. That shows that even in his 

 hundredth year he was capable of very strong feelings. Now, a Swiss 

 psychiatrist a few years ago visited all 12 centenarians who in that year 

 lived in Switzerland. He found some loss of memory, but no definite 

 mental senility. That shows the great influence of mind on body. And 

 r think one other very important point which is emphasized by many 

 pathologists is the difference, which is typical for old age, between 

 structure and function. We may find, as I found in these two cases, 

 severe changes of arteriosclerosis, and on the other hand, despite these 

 changes, very few clinical signs. I think it may add to the elucidation of 

 the problem if we study old people who reach a very great age and study 

 the compensations which make it possible to live despite severe patho- 

 logical changes. That compensation is a function which is very difficult 

 to measure, but if we could try to find out what factors it depends on, I 

 think it would add a good deal to our understanding of the pathology 

 of old age. 



Lansing: I was very much impressed with Prof. Cameron's data, 

 particularly in that they seemed to make a point that wasn't brought 

 out earlier. It appeared that the incidence of severe cancer decreased 

 steadily in each successive age group, beginning with 43 per cent and 

 winding up with 6 per cent. We have here, then, an increased capacity 

 to survive — the opposite to what one would expect in an ageing popula- 

 tion if we carry this point over to Prof. Medawar's discussion. The 

 incidence of arteriosclerosis went up steadily — ^it was at sixty-five 

 rather low and with each successive age group it went up to higher and 

 higher levels, reaching 48 per cent. Now, in your analysis in which you 

 relate arteriosclerosis to cancer cases, individuals with cancer and with- 

 out, and where you bracket the age groups sixty-five to eighty-five, I 



