200 



GROWTH OF ORGANS 



Body weight of the Norway on the body weight of the Albino. 

 Formula (49) gives the body weight of the Norway on the body 

 weight of the Albino for a limited range of Albino body weights. 



Tail length on body length. The tail length on the body 

 length has been determined by Hatai (MS '14) and is repre- 

 sented by formulas (50) and (51) for the male and female re- 



20 40 



BDBy LENGTH 



, mm. 



LLI 



240 



Chart 30 Norway rat giving the tail length on the body length. Males, 

 females. Formulas (50), (51), table 85. 



spectively. As can be seen by consulting table 85 the males have 

 the shorter tails a relation which agrees with that found for 

 the Albino. In chart 30 are given the corresponding graphs. 



Brain weight on body weight. The direct determinations of 

 the weight of the brain have been made on 232 males and 278 

 females. The general formula (52) expresses the relation of 

 brain weight on body weight for the sexes combined. 



It applies however only to rats with a body weight above 

 five grams. 



