General Discr.ssioN '20;3 



ill Oxford, because for centuries past we liave liad boys singing in 

 the choir, and I have unsuccessfully searched everywhere in our very 

 good records to find out the ages at which choristers ceased to be 

 choristers when their voices broke. 



McCance: If I could make one point about the attainment of repro- 

 ductive maturity, in relation to maturity generally, there is no doubt at 

 all that in animals you can delay the onset of sexual maturity by giving 

 them too little to eat, and in children there are a number of papers, all 

 of which go to show that the child which is over-sized and over- 

 weight attains sexual maturity considerably earlier than the normal 

 child. 



Krohti: But the reverse is also true, that if you feed animals too well 

 they are poor breeders and begin to breed later than normal. 



McCance: Yes, that is true. We are all interested in our department 

 in the fact that show animals may not breed at all. That is one reason, 

 I believe, why show breeders like to sell their animals at the show, for 

 they know they may not get the animals to reproduce. 



Olbrich: Prof. McCance, if a person gets fat after maturation, and is then 

 put on a reducing diet, does he live longer? 



McCance: I don't know. 



Sinclair: Dublin last year published a paper in a little-known journal 

 in which he analysed a large number of the Metropolitan Life Insurance 

 figures and concluded that fat people when they became thin did live 

 longer. The basis of that conclusion is a very difficult one to follow % but 

 he has written a paper precisely on that point. 



Parkes: You mean they lived longer than they would have done if 

 they stayed fat, or than ordinary people. 



Sinclair: Longer than if they had remained fat. 



Parkes: That must be very difficult to prove. 



Sinclair: I quite agree, but by a complicated analysis of his figures he 

 reached this conclusion, and in fact the title of his paper is "Fat People 

 Who Lose Weight Live Longer" (Dublin, 1953, National Vitamin 

 Foundation, Nutr. Symp. Ser. 6, 106). 



Lansing: Isn't there another interpretation, perhaps, that one who 

 goes to the trouble of trying to make himself thin is also conscious of a 

 desire for longevity, and generally looks after himself better than the 

 carouser who stuffs himself? It seems to me that Western culture has a 

 very high regard for the monastic w^ay of life, there is a moralistic 

 factor here, that it shouldn't be healthy to eat well, or to smoke, or to 

 indulge in physically pleasant activities. We never hear of the fact, 

 which seems to be true, that alcohol in moderation is conducive to 

 longevity. 



Parkes: I can suggest one technique which might be useful for study- 

 ing the relation of early increase in size to time of maturity of various 

 parts of the body, and that is the foster-mothering of newborn animals 

 from one species on to a larger species. Years ago I j)ersuaded rats to 

 rear newborn mice, mainly to see if it was a practicable procedure. The 

 results were positively staggering. The young mice at the age of three 

 weeks, when normally they would average about 7 g. in weight, were up 



