276 



THE RATE OF GROWTH 



[CH. 



will be in direct and precise proportion to the mass of the leaf from 

 which it grew. The leaf is all the while a living tissue, manu- 

 facturing material to build its own offshoots ; and we have a simple 

 case of the law of mass action in the relation between the mass of 

 the leaf with its 'included chlorophyll and. that of its regenerated 

 oifshoot*. 



16 18 20 

 days 



Fig. 87. Relation between the percentage amount of tail removed, the percentage 

 restored, and the time required for its restoration. Constructed from M. M. 

 Ellis's data. 



A number of phenomena connected with the linear rate of 

 regeneration are illustrated and epitomised in the accompanying 

 diagram (Fig. 87), which I have constructed from certain data 

 given by Ellis in a paper on the relation of the amount of tail 

 regenerated to the amount removed, in tadpoles. These data are 

 summarised in the next table. The tadpoles were all very much 



* Jacques Loeb, The law controlling the quantity and rate of regeneration, 

 Proc. Nat. Acad. Sci. iv, pp. 117-121, 1918; Journ. Gen. Physiol, i, pp. 81-96, 

 1918; Botan. Oaz. lxv, pp. 150-174, 1918. 



