POSTNATAL GROWTH 



175 



weighed only once. The original values at birth and for the 

 first ten days were plainly too high and have been replaced by 

 new data (Donaldson, '15). After the 14th day the weighing 

 of 19 males and 17 females was made at frequent intervals, so 

 long as the animals kept in good condition. 



Chart 21 Growth in body weight on age. Male albino rat. A. Observa- 

 tions of Donaldson, Dunn and Watson ('06). See table 157. B. Observations 

 of King ('15). Data from two series combined. See table 121. 



Watson's ('05) observations show that mated females gain in 

 weight about 0.03 per cent per diem faster than the unmated. 



Using the data for graphs A in charts 21 and 22 Hatai has de- 

 termined the graph for which formulas (41) and (42) give the values 

 for the male, and formulas (43) and (44) the values for the female 

 for this special series. By the use of these formulas the body 



