266 Discussion 



long life, I thought that was rather a broad inference from their 

 particular study on white rats. 



Comfort: I do not think any human population has ever been sub- 

 jected to the sort of controlled and selective restriction of diet which 

 Dr. Berg and Prof. Simms have been using. Starved populations are 

 deficient in all foods, and do not receive adequate vitamin supple- 

 ments, as McCay's rats did. There is a difference there. I agree with 

 you entirely about the general principle. 



Sacher: Restrictions in diet during and after the past war in 

 several countries may have had a relation to the observed decrease 

 in mortality from heart disease. 



Tanner: In some of the degenerative diseases, for example diabetes, 

 the incidence and the death rates went down. But this is different 

 from the notion that at the same time children are being starved and 

 therefore they might live longer later on. The starvation during the 

 war lasted a sufficiently short time, so that those children who were 

 starved probably picked up on to their natural growth curves a little 

 later on. It was acute or sub-acute starvation, which is probably 

 compensated for pretty rapidly. We know that the human, like the 

 rat, gets back to the normal growth curve fairly rapidly, even after 

 severe disease or severe starvation. It is for this reason that I do not 

 think this data is particularly relevant. 



Sacher: Nevertheless, such children constitute a cohort which can 

 be followed in successive decades. Even though normal growth is 

 resumed, there 'may still be permanent after-effects detectable in 

 later susceptibility to disease. 



Jalavisto: Did you measure the death rate at earlier dates in this 

 parental age series. Prof. Rockstein? 



Rockstein: Yes, I have curves, but this was a very limited study, 

 involving about 150 flies in each case, and so the data are not really 

 adequate for preparing such curves. 



Maynard Smith: My colleague Miss Clarke has been doing experi- 

 ments on the effect of larval nutrition on the longevity of Drosophila, 

 The animals are kept as adults in the same environment on the same 

 food, but are fed as larvae on diets varying from • 03 per cent up to 

 about 16 per cent of dead yeast. I do not think she would want to 

 commit herself very much on the results, because she has not 

 finished doing the sums. However, it is quite clear that the effect, 

 if any, of larval nutrition on adult longevity is very small. It has an 

 effect on the time it takes the animals to develop, and on how big 

 they are when they emerge from the pupae, but it has only a very 

 tiny effect on their adult survival in either sex. I confess I find that 

 surprising. 



