Page:Encyclopædia Britannica, Ninth Edition, v. 7.djvu/255

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FIG. 24. A, the lower jaw of a child between four and five years old. 5, the last mi k molar, with the successional bicuspid tooth in the cavity of reserve imme diately below it; 6 and 7, the first and second peimanent molars in their sacs; 6, the cavity in connection with which the wisdom tooth is formed. B, the lower jaw &quot;of a child about six years old; 6 and 7, the first and second per manent molars; 8, the papilla of the wisdom tooth developed in connection with its cavity 6. From Goodsir

1em 1em 1em 1em  DIGITALIS, or, a genus of biennial and perennial plants of the natural order Scrophulariacece. The common or purple foxglove, D. purpurea, is common in dry hilly pastures and rocky places and by road sides in various parts of Europe ; it ranges in Great Britain from Cornwall and Kent to Orkney, but it does not occur in Shetland or in some of the eastern counties of England. It flourishes best in siliceous soils, and is not found in the Jura and Swiss Aips. The characters of the plant are as follows : stem erect, roundish, downy, leafy below, and from 18 inches to 6 feet or more in height ; leaves ilternate, crenate, rugose, ovate or elliptic-oblong, and of a dull green, with the under surface downy and paler than the upper ; radical leaves together with their petioles often i foot in length ; root of numerous, slender, whitish fibres ; flowers lf-2/ inches long, pendulous, on one side of the stem, purplish crimson, and hairy and marked with eye-like spots within ; segments of calyx ovate, acute, cleft to the base ; corolla obtuse, with the upper lobe entire or obscurely divided ; stamens four and didynamous (see ., ); anthers yellow and bilobed ; capsule bivalved, ovate, and pointed ; and seeds numerous, small, oblong, pitted, and of a pale brown. As Parkinson remarks of the plant, &quot; It flowreth seldome before July, and the seed is ripe in August ; &quot; but it may occasionally be found in blossom as late as September. In one variety, common in gardens, the flowers are white ; in another their purple is of a coppery or metallic hue ; and not unfrequently in cultivated plants several of the uppermost blossoms may be united together so as to form a cup-shaped compound flower, through the centre of which the upper part of the stem passes. A figure of D. ptirpurea will be found in. . Many species of foxglove with variously-coloured flowers have been introduced into Britain from the Continent. The plants may be propagated by off-sets from the roots, but are best raised from seed. The foxglove (Ang.-Sax., foxes-dife, foxes-glofa) is known by a great variety of popular names in Britain. In the south of Scotland it is called bloody fingers ; further north, dead-men s-bells ; and on the eastern borders, ladies thimbles, wild mercury, and Scotch mercury. Among its &quot;Welsh synonyms are menyg-dlyllon (elves gloves), menyg y llwynog (fox s gloves), bysedd cochion (red lingers), and bysedd y civn (dog s fingers). In France its designations are gants de notre dame, and doigts de la Vierge. The German name fingerhut (thimble) suggested to Fnchs, in 1542, the employment of the Latin adjective digitalis as a designation for the plant. The leaves, gathered from wild plants when about two- thirds of their flowers are expanded, deprived usually of the petiole and the thicker part of the midrib, and dried, constitute the drug digitalis or digitalis folia of the pharmacopoeia. The prepared leaves have a faint odour and bitter taste ; to preserve their properties they must be kept excluded from light in stoppered bottles. They are occasionally adulterated with the leaves of Inula Conyza, Ploughman s Spikenard, which may be distinguished by their greater roughness, their less divided margins, and their odour when rubbed ; also with the leaves of Symphytum oflicinale, Comfrey, and of Verbascum Thapsus, Great Mullein, which unlike those of the foxglove have woolly upper and under surfaces. The powder, infusion, and tinc ture of digitalis are employed both externally and inter nally ; and its active principle, digitalin, may further be used for subcutaneous injection. Digitalin, according to Nativelle, is a crystallizable, neutral, inodorous, bitter substance, of the formula C 05 H 40 15, insoluble in water and ether, but soluble in alcohol and chloroform. The earliest known descriptions of the foxglove are those given by Fuchs and Tragus about the middle of the 16th century, but its virtues were doubtless known to herbalists at a much remoter period. Gerarde, in his Herbal (1597), advocates the use of foxglove for a variety of complaints ; and John Parkinson, in the Theatrum Botanicum, or Theater of Plants (1640), tells us that