236 



Kenji nittono 



Each age group contains measurements obtained from seventy- 

 five of the largest ganghon cells contained in three ganglia belong- 

 ing to two rats of the same age. Table 4 gives the same data 

 arranged according to the mean body weight taken from two 

 rats of the same age. The data from the rats 385 and 485 days 

 old have been omitted from tables 3 and 4 because they repre- 

 sented only single individuals. 



Chart 1 shows graphically the data given in table 3 in which 

 the ordinates give average diameters of the cell bodies and the 

 nuclei of the gasserian ganglion on age. I have entered also 



Chart 2 Based on table 4 and giving on body weights the diameters of the 

 largest cells from the gasserian ganglion of the albino rat and of their nuclei. 



on this chart the observed body weights and the brain weights 

 (computed) normal to the age. 



Chart 2 shows graphically the data given in table 4 in which 

 the diameters of the cell bodies and the nuclei are plotted on the 

 average body weight. The graphs given in these two charts 

 show shght differences in detail, yet the general relations are 

 similar. On these charts three phases may be distinguished in 

 the growth of the cell body and the nucleus." The first phase 

 is represented by a very rapid growth of the cell body to about 

 the first twenty days after birth. 



In the second phase the rate of growth diminishes, but still 

 continues to be fairly rapid to about seventy-five, to eighty days 



