m. 640] BODY SIZE AND ORGAN SIZE 397 



ture plants studied, wliicli included everything from seed- 

 lings to plants eoming into flower, there is naturally a 

 very close relation bi'twcen body size and growing i)oint 

 size, since these indi\-i<lii;ils all hclonu- to tiiat ])()ili()ti of 

 the plant's life liistorx- wiiciv ils i)i'iiii;ir\- yrowitm' points 

 are progressively iiu-rcn-iim' in (llanH'tcr. the niaximuni 

 being attained in hcan- '\u>\ hd'oi-c the blooming period. 

 It would b(> onl\ iiatiirnl that in this group of plants in 

 which both body size and urowing i)oint size are pro- 

 gressively i-ising. tlicri^ should be a high correlation be- 



This liy I lot he-Is of a direct relation between the size 

 of an origan and the size of the growing point from 

 wliicli it arose will evidently explain the facts which we 

 have ol)served in the case of our bean plants. Tlie 

 problem now remains to discover a means whereby we 

 may determine more directly the soundness of the hy- 

 pothesis. The size of an organ can be measured fairly 

 accurately either by weighing it or l)y determining rts 

 dimensions and com])uting its volume. To get a moas- 

 ureniriit which shall represent at all ade(|uately the size 



