170 GROWTH OF PARTS AND ORGANS 



Body weight on age in days — mated females = 



8.071 + 0.367 age + 0.0131 Age* (36) 



[10 < Age < SO] 



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



[80 < Age <3Q5] 

 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 xo 11 ! 1188 ^ 05865 ^- 1 )- 05651 ^- 1 ) 2 } ( 38 ) 

 [Age < 95] 



Weight of thymus = 



0.3903 - 0.00139 (age) + 0.00000128 (agey (39) 



[Age > 95] 

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



Percentage of 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* (Phase 1) (40) 

 [10 <Age <40] 



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

 [40<^e<160] 



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

 [160<A^e<365] 



