62 



ANATOMY 



These changes in resistance are related to the adjustment of 

 the red blood cells, and to the water content of the serum nor- 

 mally surrounding them at the different ages, Hatai ( J 18). 



PERCENTAGE OF WATER 



AGE DAYS 



SO 



100 



150 



200 



250 



300 



350 



400 



450 



Chart 4 Showing the percentage of water in the serum of the albino rat 

 at different ages. 



TABLE 26 



Giving the concentration of the hypotonic salt solution which just produces 20 per 

 cent hemolysis of the rat erythrocytes, based on the seven age groups 



A. Percentages according to age Sexes combined. 



B. Percentages according to age- Males and females separately, in twenty- 

 three pairs of determinations. 



The concentration of hypotonic salt solution which causes 

 approximately 20 per cent hemolysis is 0.441 per cent for the 

 youngest and 0.470 per cent for the oldest group. As appears 



