llO M. Victor Parker, et ah 



When the body water compartments are related to total 

 body water as a standard of reference another sex difference 

 appears. In males the extracellular water accounts for 43 per 

 cent of total body water and in females for 47 per cent, 

 whereas the intracellular water amounts to 57 per cent of 

 total body water in the males and 53 per cent in the females. 

 The difference between these ratios is statistically significant 

 (P< 0-001). This difference in the distribution of the total 

 body water between the extracellular and intracellular 

 compartments can be explained as the result of a higher 

 development of tissues rich in intracellular material and 

 relatively poor in extracellular phase, such as muscle tissue, 

 in the males. 



In conclusion: the sex difPerence in body composition is 

 outlined as a higher relative content of total body water, a 

 higher relative content of intracellular water and a lower 

 relative amount of total body solids and especially of body 

 fat, in males than in females. The total body water is distri- 

 buted with a lower extracellular fraction and a higher intra- 

 cellular fraction in males than in females. 



Ageing 



Our experiences in the old age group are based upon the 

 investigations carried out in seven apparently normal males 

 with an average age of 75 years and seven apparently normal 

 females with an average age of 68 years. This group was 

 studied in Dr. Francis Moore's laboratory (Parker, Olesen and 

 Moore, 1958). The methods used were the same as those 

 applied to the younger adults. 



The essential findings in the old age group are presented in 

 Table VI. 



A comparison between younger and older adults reveals the 

 following findings : total body water decreases from 54 • 3 per 

 cent to 50 • 8 per cent in males and from 48 • 6 per cent to 43 • 4 

 per cent in females. The extracellular water rises slightly in 

 males and decreases slightly in females. The intracellular 

 water decreases from 30 • 9 per cent to 25-4 per cent in males 



