Dec, 1908.] 



The Effect of Alkaloids. 



407 



tions of atropine and strychnine, such as were obtained bv 

 means of filtrating these solutions through lamp black or through 

 calcium carbonate (1), the process of regeneration was aug- 

 mented to a remarkable degree. Solutions of strychnine (Fig. 

 4) act differently upon different plants, but the greatest stimu- 

 lation is caused invariably by the weaker solutions. Stronger 

 solutions, though they may stimulate growth at first, soon 

 become injurious to the plant. 



At the end of twelve days after the operation the differences 

 in size of the regenerating plants became much more pronounced 

 than those seen in the figures shown here. 



In the following table are given the data concerning the 

 green and d,ry weight of the plants. 



Table II. 



Solution 



Strychnine 

 Digitalin 

 Pilocarpine 

 Atropine 



Control I 

 Control II 



2.25 

 3.75 

 (1.65 

 2.95 



2.40 

 1.85 



0.56 

 0.94 

 1.64 

 0.74 



0.60 

 0.46 



3.50 

 4.80 

 5.05 

 2.25 



1.25 

 1.93 

 1.49 

 0.81 



It may be seen from this table that the inference which should 

 be drawn from records of the weight of the regenerated stems 

 practically coincides with data obtained from the studv of their 

 transpiration and actual size. 



On the loth of March, i. e., seventeen days after the operation 

 the regenerated stems were cut off once more with sharp scissors 

 near their proximal ends. The object in performing this experi- 

 ment was to find out how the plants would behave in regeneration 

 after a second operation. In a previous work on regeneration in 

 the fresh water oligochaete, Lumbriculus, (5a) it was pointed out 

 that the rate of regeneration in that animal decreases after suc- 

 cessive operations, so that if we designate the rate of regeneration 

 after the first operation by a unit, the rate of regeneration after a 

 second operation would be only one-half of a unit, and one-fourth 

 of a unit after the third operation, the length of. time during 

 which the animals are allowed to regenerate being, of course, the 

 same in all three cases. Zeleny (S), on the other hand, finds that 



•» i 



