196 



GROWTH OF PARTS AND SYSTEMS 



TABLE 83 



Norway rat — Percentage of total body weight represented by the weight of integument, 

 ligamentous skeleton, musculature, viscera and remainder. (Jackson and Lowrey, 

 '12) 



1 Including gravid uterus, which weighed 13.76 grams. 



2.) Growth of systems. When the values for the five entries in 

 table 83 are compared with the last four in table 50 for the albino 

 rat, it is noted that in the Norway the values for the musculature 

 and viscera are high, while that for the 'remainder' is low. 

 This last difference is due in part to the smaller amount of fat 

 in the Norway. At the same time there is other evidence to 

 show that for the same body weight as the Albino, both the 

 trunk and the viscera of the Norway are heavier, as here found. 



3.) Weight of cranium. (Donaldson, '12.) Determinations 

 of the weight of the cranium dried at room temperature have 



TABLE 84 



The mean weight in grams of the crania in each body weight group of the four series 

 of wild Norway rats from Paris, London, Philadelphia, Vienna (based on table 1 

 Donaldson, '12 a.) Each weight group is based on six cases; S males and 8 females 



For the corresponding weights of the albino crania see table 55. 



