94 Discussion 



with people who were keeping themselves on an ordinary kind of regime 

 they would show up in spite of any day-to-day variations. That is 

 certainly a deficiency in our studies, but I do not think it entirely 

 invalidates them. 



Adolph : I would like to go further and suggest that if the balances or 

 the outputs reflect variations of intake, they might be just as valuable as 

 variations of output would be on a constant intake. 



Thaysen: How were the Na/K ratios in the saliva done? 



Swyer: They were obtained by collecting saliva first thing in the morn- 

 ing, as nearly as possible at the same time each day, for a fixed length of 

 time (five minutes). In one series, the first five minutes was collected, 

 and in another series the first five minutes was discarded and the second 

 five minutes collected, as I understand there is something significant in 

 that. We were unable to see any difference at all when done in these two 

 ways. The saliva was collected just by spitting into a bottle, and the only 

 stimulation was that the patients were chewing paraffin. 



Thaysen : Your Na/K ratios showed very great fluctuations and it was 

 difficult for me to assess any cyclical change. The Na/K ratio may vary 

 considerably just because of changes in the rate, and these variations 

 are quite independent of hormonal or other influences. I do not think 

 that the estimation of the Na/K ratio permits one to dispense with the 

 necessity for measuring secretory rate. 



Swyer : Another thing we did was to measure the volumes which were 

 produced in this fixed time, and try to correct for the variations in 

 volume. It did not seem to make any difference at all, but I do agree 

 that some of the variables might have been inadequately controlled. 



Thaysen: I believe that you might find the ratio very reproducible 

 when you use a standard secretory rate. 



Talbot: Dr. Swyer, you mentioned something about a will-o'-the-wisp, 

 sodium diuretic hormone of adrenal origin. Do you believe in its exis- 

 tence, and if so, have you or any of those here a solid notion as to the 

 nature of the beast? 



Swyer: I certainly have no solid notion. It is an idea that has been 

 mooted to account for the apparent inability of normal amounts of 

 sodium-retaining hormone to counteract the sodium loss. I know there 

 have been very active searches for it, and that large amounts are found 

 in the salt-losing type of adrenal hyperplasia. 



Desaiilles : We have worked quite a lot on this problem and we have 

 got something which is derived from the adrenal, but what it is we do not 

 really know. Dr. Wettstein (1958. Iva., 29, in press) has just described 

 how he found it and how he is working on it, but that is as far as we 

 have got. 



Adolph: I would like to raise a general problem which Dr. Swyer 

 brought up. How is one to judge whether in labour there is dehydra- 

 tion? All the criteria by which we can judge of the existence of dehy- 

 dration would be in a very fluctuating state at such a moment, and I 

 realise that Dr. Swyer was not making any positive statements about it. 

 Is there any way in which we can judge hydration, dehydration or super- 

 hydration, as transitory states of the organism? 



