History.—The rhizome of Dioscorea villosa is a favorite therapeutical agent among Eclectic physicians, who have advantageously used it for more than 60 years. It is known as wild yam and colic root. The first specimens employed were from the Dioscorea villosa, with pubescent leaves (Fig. 97), and now known as the true wild yam. About the year 1850, botanic druggists noticed the admixture by root-diggers of the rhizomæ represented by (Fig. 97, 1), and for a considerable time rejected it as an adulteration. The diggers insisted, however, that both “roots” were obtained from vines almost identical in appearance (although they can distinguish between them), and finally purchasers were compelled to accept them, more especially as the true rhizomæ became very scarce. The late Mr. H. M. Merrell, of Cincinnati, Ohio, to whom we are indebted for this information, stated that the first heavy shipments of the false “wild yam” root to Eastern houses were made about 1860, which article purchasers refused to accept, but after some correspondence, coupled with the fact that the true wild yam root could not at that time be obtained, the parties concluded to receive it. Since then the two rhizomæ have been sold indiscriminately, although but little of the original drug is to be found in the market. Eclectic physicians are aware of the difference between these rhizomæ, and refuse to use the “false” variety, insisting that it does not possess the medicinal properties, and can not safely be substituted for the “true.” In this connection, we invite attention to the accurate engravings of each variety of the rhizomæ in Fig. 97.
The root loses its therapeutical virtues after the first year, and hence should be freshly gathered every year, and carefully dried. Water or alcohol extract its virtues. Several species of Dioscorea yield edible rhizomæ, generally known as “yams.”