CULTIVATION OF MEDICINAL PLANTS. 739 



guarana, digitalis, the Solanaceous leaves, etc. In some cases 

 the increase in quality can be determined by the assay of some one 

 constituent, but in other cases the acquired value, like that of teas, 

 wines, and tobacco, cannot be determined by an assay process and 

 yet can be detected by the expert. 



It has already been pointed out that plants contain a large 

 proportion of water, and when they are collected and dried there 

 is necessarily considerable loss. The loss is greater in the case 

 of herbaceous plants, where the yield of crude drug is only about 

 10 per cent., as in eupatorium and stramonium. Roots and rhi- 

 zomes yield on an average from 20 to 30 per cent, of dried drug. 

 In some cases, as in hops, the yield of dried drug is over 60 per 

 cent., and in fruits and seeds there is very little loss. 



RELATIVE VALUE OF DRUGS FROM CULTIVATED AND WILD 

 PLANTS. For some years it has been a question whether the 

 activity of drugs obtained from cultivated plants is equal to that 

 of those derived from wild plants. We find in some of the 

 foreign pharmacopoeias the specific statement that certain drugs, 

 as digitalis, belladonna leaves, and belladonna root, must be 

 derived from wild plants. This would naturally lead to the infer- 

 ence that wild plants are better, and yet it may be that this 

 provision was made with the intention of securing uniformity 

 of drugs rather than because the materials from wild plants are 

 superior. In 1907 Rippetoe conducted some experiments in Vir- 

 ginia which showed that cultivated plants of belladonna yielded 

 both leaves and roots which were equal, if not superior, to the 

 average drug on the market. As this work was done without any 

 particular care and in a limited way, it was more than gratifying 

 to those who were especially interested in this subject. Carr has 

 shown by careful comparative experiments that cultivated plants 

 of belladonna contain a little more alkaloid than do the wild 

 plants. The investigations of Sievers also point to a similar 

 conclusion. Sievers has also shown that the percentage of alka- 

 loids in the leaves of different cultivated plants is exceedingly 

 large, and that plants high in alkaloids will continue to breed 

 plants high in alkaloids, so that by mere selection a better com- 

 mercial article may be produced. Coming to the question of 

 digitalis, there are some very interesting results. Hale, for in- 



