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The Improvement of iMedicinal Plants. 



F A. Miller. 



The ]irinciiil<.'s (•!' plant breeding Inive a.s yet luirdly been bi'DUght to 

 bear iiiuni Uie improvement of medicinal plants. Tlie necessity of im- 

 provement and tbe possibilities of the application of inodern methods of 

 breeding to this group of ])lants has led the writer to undertake a series 

 of investigations upon this su])ject. A discussion of the results and prog- 

 ress of these investigations is the object of the present paper. 



The bioadening influence of plant breeding is gradually bringing 

 under control members fi-om all groups of the plant kingdom, and it is 

 only fitting that this very important group of i)lants should be made to 

 yield the best of nature's possibilities. That the group contains many 

 plastic forms which will yield readily to modern methods of breeding is 

 evidenced by the fact that some of the most potent medicinal forms ap- 

 pear in families from which have been obtained many valuable horticul- 

 tural varieties. The Solonacea' for example, with the genera Atropa. Hyo- 

 scyamus. Datura, Solauum and Capsicum, and the no less important Scro- 

 phulariaceiTe containing the now widely known genus Digitalis, which is 

 found to be equally as variable both in chemical and physical character- 

 istics as the common garden forms derived from the same and related 

 genera, will serve to illustrate this point. 



A review of the literature on drug plant improvement reveals but 

 few attempts at systematic investigation by the employment of standard 

 methods of breeding. On the other hand much has been written and no 

 little accomplished upon the introduction and cultivation of medicinal 

 plants. Introduction and cultivation with no improvement has been the 

 order of procedure. It is (juite true that some improvement has resulted 

 from a changed environment and a reduced struggle for existence, but not 

 through the intensive application of particular methods. Improvement by 

 means of seed and plant selection, the isolation and testing of favorable 

 varieties, the study of soil and climatic conditions, trials in hybridization, 

 grafting, or other methods which might prove applicable, have not been 

 tried except in comparatively few instances. Had the government made 



