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A TEXT-BOOK OF BOTANY. 



stance, showed that cultivated digitalis leaves yield a much higher 

 potency than those obtained from wild-grown plants, and yet 

 he concludes that it is doubtful whether the fact that they were 

 cultivated had anything to do with the high activity. One of the 

 most valuable facts brought out in connection with these experi- 

 ments is that the leaves of one-year-old plants seem to have as great 

 toxicity as those of the two-year-old plants. Hale distinctly states 

 that " first-year leaves are not necessarily weaker than second- 



FlG. 408. Atropa Belladonna, first year's growth from seed planted January ist. 

 Photograph in July of the same year. From the Experimental Farm of Eli Lilly & Com- 

 pany, Indianapolis, Ind. 



year leaves, and might be used in preparing assayed digitalis prepa- 

 rations." This means that one does not have to wait two years 

 before securing a crop, so that practically one can obtain twice the 

 quantity of the drug during the same period. 



There may be some instances during this experimental stage 

 which might seem to indicate that certain external conditions, such 

 as climate as well as soil, have a very great influence in the growing 

 of plants of exceptional value. In the case of American-grown 

 cannabis, Eckler and Miller have shown that repeated plantings 



