MILLER: THE PROPAGATION OF MEDICINAL PLANTS 121 
Table III gives results obtained by the vegetative method 
of propagation for belladonna and other miscellaneous forms. 
Open field seeding has been found practical for such forms as 
stramonium (Datura Stramonium), cannabis indica (Cannabis 
sativa), larkspur (Delphinium Consolida), and lappa (Arctium 
Lappa). This list can probably be greatly enlarged as other 
forms are tested. 
Various species and varieties of the genus Datura are being 
investigated in the same manner as belladonna and digitalis. 
Fifty individual plant assays have been made from plantings of 
Datura Stramonium and Datura Tatula. These indicate that the 
application of plant breeding methods to the improvement of 
medicinal plants may be successful, and extremely practicable. 
Averages of 50 per cent. and 60 per cent. have been obtained 
from the progeny of selected parent plants of Datura Stramonium 
and of 49 per cent. and 62 per cent. from Datura Tatula as com- 
pared with averages of 28 per cent. and 35 per cent. obtained 
Tespectively from wild plants of these two species. Individual 
plants have been found which assay as high as 65 per cent. for 
the D. Stramonium and 77 per cent. for D. Tatula. Such indi- 
viduals are used for propagating purposes. Again, as in the case of 
belladonna, it is a question of inheritance that must determine the 
method of propagation or the advisability of attempting to per- 
petuate these high yielding individuals for commercial purposes. 
In the foregoing, propagation has only been considered as 
a necessary preliminary procedure to other more comprehensive 
Problems. A sufficient number of methods for propagating various 
Classes of plants has been developed to suit the present need of 
medicinal plant growers. These have been largely the result of 
certain demands upon well-established horticultural forms, and 
their extended use is only a matter of application. 
Their application herein described has furthered investigations 
not otherwise possible. The results obtained from their applica- 
tion, the continuation of other related problems, and the objects 
in view, have all been stated. The related problems such as 
commercial production, the testing of different species and 
Varieties, and their improvement by breeding and selection, have. 
an unquestionable economic value, the solution of which will lend 
