366 



GROWTH OF ORGANS IN RELATION TO BODY LENGTH 



6. The computed number of cells in two layers of the cerebral 

 cortex — wild Norway rat — Sugita {'18a). Proceeding in the same 

 manner as in the case of the Albino, see p. 83 the computed 

 number of nerve cells in the cortex of the Norway rat was 

 obtained at different brain weights. The data are arranged in 

 table 198. 



TABLE 198 

 Giving the computed nuviher of nerve cells in two layers of the entire cerebral cor- 

 tex of the Norway rat brain, obtained on the basis of the measurements given in 

 this series of studies. These values are made to be comparable with the corre- 

 sponding values of the computed number of nerve cells in the cortex of the albino 

 rat brains of like brain weight groups. {See table 48) 



*As remarked in a note to table 48 the number given in this column corre- 

 sponds to 1/100 oiNX L.F.X W. DXT,or 1/50,000 of the actual number of cells 

 contained in the computed volume of the cortex. 



{a) Comparison with Albino. On examining table 198 column 

 E, it is seen that the number of nerve cells in the cortex is nearly 

 complete at a brain weight of 1.37 grams (Group N. XIII) while 

 in the Albino this condition was reached at a brain weight of 1.17 

 grams (Group N. XI). As the last line in table 198 shows, the 



