32 



C. M. JACKSON 



The large but irregular variability of the liver in the present 

 data is shown in table 9. The coefficient of variation in abso- 

 lute weight appears at different periods from 18.6 to 40.8, but 

 with no definite change according to age or sex. The variation 

 in the percentage weight is seen to be, as a rule, very much less. 

 Accordingly, the coefficient of correlation between liver and body 

 weight is high, from 73.6 to 96.8 (high figures, however, partly 

 due to 'spurious correlation'). 



Fig. 3 a THYROID GLAND Percentage of body weight 

 Curve derived from Hatai's formula (both sexes). 

 Means at seven age periods from Jackson's data; males, 0, females, 



Fig. 3 b SPLEEN Percentage of body weight 



Curve denved from Hatai's formula (males, enlarged spleens excluded). 

 Means at seven age periods from Jackson's data; males. 0, females,®. 



5 10 20 



100 150 



Body weight m grams 



9. Spleen 



The relative (percentage) weight of the spleen, calculated from 

 Hatai's ('13) formula, is represented by the curve in figure 3 b. 

 It is seen that the spleen increases in relative size from 0.16 per 

 cent of the body weight at 5 grams to 0.30 per cent at 10 grams, 

 and a maximum of 0.32 per cent at 20 grams, thereafter decreas- 

 ing slowly to 0.30 per cent at 50 grams, 0.28 per cent at 120 

 grams, 0.27 per cent at 200 grams, and 0.26 per cent at 300 to 

 500 grams. 



