316 



cum. cainidior, lea, tobacco and a liost of other forms l)ear.s out the evi- 

 dence of the foregoing, and furnislies tlie worker with a weallli of data 

 apjilicable in many wa.vs to drug plant improvement. 



Tlie drui; digitalis, consisting of tlie dried leaves of l»igitalis pui-pure i 

 r.. collected from tlie second .vear's growth at the coiiunencenient of flower- 

 ing, is equally in need of improvement. Physicjlogical tests Iiave shoxvn 

 a variation in the toxicity of preparations made from drugs represent i !•/ 

 diffei'ent geographical sources. Differences of opinion also exist as t i t'l,' 

 relative medicinal value of first and second year leaves, of those fr.ir.' 

 v.'ild and cultivated plants and of those from plants of difJ'erent specie's 

 and varieties, as well as to the effects of different periods of coUectin,' 

 and methods of curing. packLng and storing of the crude drug and t"i • 

 veJative value of preparations imide from fresh and diy leaves. .V ])ot m 

 ical examin.atioi! of the genus reveals conditions which will projialily ac- 

 ci.unt. in part at least, for the above differences of opinion. 



The genus is a largi' one, consisting of twenty-one widely distiibntel 

 species, a fact wliidi ;ilone increases the possibilities of an admixtui'r o 

 leaves from several species or from the same species growing under diftv'r- 

 ent climatic conditions. This p;)ssibility is also increased by thi' innneroiis 

 Aarieties originated liy florists and gardeners who have no; bi-en slow in 

 recognizing (he aesthetic value of the genus. Their eatalogues now con- 

 tain many standard varieties which are noted for their attractive nature 

 and ease of culture. The official si)ecies Digitalis purpurea L. has figured 

 largel.v in this pnidui ( ion, lia\ irg given rise to no less than half a dozen 

 distinct forms winch are niiw listed as hardy perennials. (»llier sjieeies 

 have been active in this resi)ect but have not produced such a diversity 

 (.f forms. This jiroiierty of a genus to yield ninltijile forms is strongly 

 suggestive iM" a wid'- rang.' of variations in the rnrri'siionding pt^reentag.^ 

 of active jiriiu ipN s. Tiie bnlanical inspi'cfion of tlie ei'ude drug is in n;) 

 degi'ee indic-itiNC of lliis pi'icentage of .-iriivc principle, but that such ai 

 indication is ])ossil»le is suggcf-tcd by lecent investigations of tJregory 

 n|ion flit" association nf f i-.insmissilile characters in Trinmla sinensis, wlie e 

 ii has been shown Unit some characters ;ire ;ilways found to accompany 

 others Willi recurring ii'gularity. r.iil until such a c'onveiueiit relation is 

 found to exist i)i'(ween active principle and specific morphological char- 

 acters, the botanical e.xaminat ion can only jminl to the possible source 

 aiid iiol III tiif coinparalixe medicinal \:ilne of the drug. 



