230 



TWENTY-FIRST REPORT. 



TABLE 3 



Soil Moisture, Nitrogen, Volatile Matter and Acidity. 



CONCLUSIONS. 



The following conclusions are derived partly from tlie data in Tables 1 

 to 3 and partly on plienological and collection data not fully noted previously. 



1. It will be seen that sunlight as a growth factor varied greatly. It 

 was most favorable for the growth of Podophyllum peltatum in colony number 

 two, as judged by total annual growth of rhizomes and numbers of branches. 



2. Conversely, the largest amount of light has a limiting effect on the rela- 

 tive amoimt of resin and nitrogen content, as shown by colony number 2, 

 Table 1. 



3. Total nitrogen of soil and other factors, e. g., fewer competitive plants 

 also favor larger rhizome growth in colony 2, and may possibly be correlated 

 inversely with lower resin content than was found in colony number 1. 



4. Low resin content in colony number 2 is a disadvantage to the manu- 

 facturer to the extent of from 15 to 30%, while it is to the advantage of the 

 collector in that total resin is larger in amount, while at the same time it takes 

 less effort to collect a given amount of 'the crude drug. 



5. Conversely, colony number 3 is relatively economically extracted, but 

 it requires from three to five times as much effort in collection as colony 

 number 2, since the rhizomes are much smaller, are less numerous, and dry out 

 more completely. Of the three colonoies, number one is perhaps the most 

 equitable to both parties, if prices are uniform for crade drug. 



6. High resin content in plants of colony number 3 seems to be correlated 

 with limited metabolism and low ash in the resin, and these are undoubtedly 

 conditioned by lack of light and probable low transpiration. No atmometers 

 were used in this work to determine actual transpiration. 



7. Date of maximum resin content for autumn collection of drug seems 

 to be from October 1st to lOtli in normal seasons. This agrees closely wtih 

 unpublished data of F. A. Miller, who found an autumn and a spring maximum. 



More extensive analyses covering several seasons and soils are desirable, 

 and the bearing of drug plant breeding and soil analysis must also be thor- 



