170 GROWTH OF PARTS AND ORGANS 



Body weight on age in days mated females = 



8.071 + 0.367 age -f 0.0131 Age 2 (36) 



= 343 log Age - 0.41 Age - 498.8 (37) 



[80<A0e<365] 

 Formulas (34) (35) (36) (37) were used for table 62. 



WEIGHT OF THYMUS ON AGE (HATAI, '14) 



Weight of thymus sexes combined = 



0.01 X lO 1 - 1 ! 1 ' 1884 ^ 5865 ^- 1 )- - 5651 ^- 1 ) 2 } ( 38 ) 

 [Age < 95] 



Weight of thymus = 



0.3903 - 0.00139 (age) + 0.00000128 (age} 2 (39) 



[Age > 95] 

 Formulas (38) (39) were used for table 72. 



PERCENTAGE OP WATER IN BRAIN. HATAI (MS '14; 

 The formulas do not apply to rats under ten days of age. 



Percentage of water in brain (male) = 



92.122-0.614 Age +0.00739 Age 2 (Phase 1) (40) 

 [10 <Age <40] 



= 82.756-2.103 log Age (Phase 2) (41) 

 [40<4gre<160] 



= 77.671 +0.00537 Age -0.000016 Age 2 (Phase 3) (42) 



