316 



cum. camphor, tea. tobacco anrl a host of other forms bears out the evi- 

 dence of the foregoing, and furnishes the worker with a wealtli of data 

 applicable in many wajs to drug plant improvement. 



The drug digitalis, consisting of the dried leaves of Digitalis purpurea 

 r.. collected from the second year's growtii at the commencement of flower- 

 ing, is equally in need of improvement. I'hysiological tests have shown 

 a variation in the toxicity of preparatic.ns made frc^m drugs represent! ig 

 difl'erent geogiaphical sources. Differences of opinion also exist as tj t'-i.> 

 relative medicinal value of first and second year leaves, of those i'roii' 

 wild and cultivated [ilants and of those from iilants of different speclp-; 

 .•nid varieties, as well as to the effects of different periods of collecting; 

 and methods of curing, packing and storing of the crude drug and t'\ 

 relative value of preparations made from fresh and diy leaves. A hot in 

 ical examination of the genus reveals conditions wiiich will iiroliably ac- 

 (•(iuiit. in part at lea.st, for the above differences of dpinion. 



Tlie genus is a large one, consisting of twenty-one widely disti ilnile 1 

 species, a fact whitli alone increases tlie possibilities of a:i admixture o' 

 leaves from several species or from the same sj)ecies growing undi'r differ- 

 ent climatic conditions. This possibility is also increased by ll^e numerous 

 varieties originated by florists and gardeners who have not been slow in 

 recognizing the aesthetic value of the genus. Their catalogues now con- 

 t!;in many stnndard vaiMeties whicli are noted for their attractive nature 

 and ease of ciilturi'. The oliicial species Digitalis purpurea I>. has ligured 

 largel.v in tiiis pi-(;du< ti.in. ha\irg given riso t i no less thiui half .-i dozen 

 distinct forms which are nnw listed as liaidy perennials. ()(liei' sjiecies 

 liave been active in this resiieet but liavi' not i>roduced such a diversity 

 of forms. This jiroperty of a genus to yii'ld nuiltiple forms is strongly 

 suggestive of a wide range' of variations in the corresponding percentage 

 of active i»rin.cipl(s. The botanical inspection of the crude drug is in n:i 

 degree indicative of this ir.-icentage of active iirinciple, but that such ai 

 indication is possible is suggested by recent investigations of (Jregory 

 I'.pon the association of transmissible characters in rrinnila sinensis, whe e 

 ii has been shown that some characters art' always found to acconi])auy 

 (rthers with recurring regularity. lint until such a convenient relation is 

 found to exist between active principle and specific mori)hological char 

 acters, the botanical examination can only i)oint to the possible source 

 and not to the comparative medicinal value of the drug. 



