Concluding Remarks 313 



emphasized, that is the way in which we regulate both output and 

 input. 



The Chairman created a precedent by quoting from a minor poet 

 last night, and I would like to quote from a major poet. Shakespeare 

 was, I think, a very good physiologist, and he described age by saying 

 "when age hath drunk his blood and filled his brow with lines and 

 wrinkles". Now those are two aspects that we have ignored. We 

 have been told about the extracellular volume but not whether the 

 blood volume has changed in age ; the wrinkles of the brow I think 

 must be determined partly by extracellular water, and also by the 

 state of the collagen under the skin. 



Swyer: As one of those who have something to do with hormones I 

 have been struck by one or two points more forcibly than by others 

 in this conference. When hormones are considered in relation to 

 electrolyte metabolism in ageing and with regard to sexual differences 

 it seems to me that we have two sets of data, both incomplete. One 

 of them relates to changes in hormone production with age and sex, 

 and the other to changes in water and electrolyte metabolism with 

 age and sex. For example, we have the data on body compartments 

 that Dr. Olesen gave us, which were very interesting indeed, and I 

 wish I had known more about that side of the problem before I set 

 about my own task. We have, too, the experimental evidence on the 

 development of hormonal responses with age and sex, and on this 

 point I feel there is something very fascinating which was touched 

 upon in the discussion but not sufficiently elaborated. I feel that we 

 need to determine more precisely the exact effect of sex, whether 

 it is indeed hormonal or genetic. I would like to suggest to Dr. 

 DesauUes that an interesting extension of his experiments might 

 be to carry them out on rats which had been castrated in utero by the 

 technique of Jost, and subsequently had their sex determined by the 

 cytological techniques which are now so readily available. 



Another point which I thought was brought out very well by Dr. 

 Fourman was this question of the differential action of Cortisol and 

 aldosterone, the one liberating potassium in the cells as a result of 

 protein catabolism, and the other altering the renal exchange of 

 sodium and potassium. The importance of taking this into account 

 in attempting to use urinary Na/K ratios as a measure of these 

 salt-retaining hormones was emphasized. 



I feel I should say a little about some of the things which were not 

 quite left out but almost so: calcium seems to have come in for 

 remarkably little attention during this colloquium, and I think the 

 only mention of the parathyroid glands was made by Dr. Kennedy 

 this morning. It is true that the parathyroids have no effect on 

 water metabolism except in highly abnormal states, but like some 



