736 MANUAL OF POISONOUS PLANTS 



leaves petioled, upper oblong, linear and entire; floral leaves like those of the 

 stem but reduced; flowers axillary and solitary, white; capsule orbicular. 



Distribution. A common weed in fields in eastern North America from 

 Nova Scotia to Florida, Missouri, Kansas, Texas, British Columbia and Cal- 

 ifornia. Also found in Mexico, South America and in Europe, almost cos- 

 mopolitan. 



Veronica virginica L. Culver's Root. Culver's Physic 



A tall, smooth, or occasionally somewhat hairy perennial, simple stem; 

 leaves lanceolate pointed in whorls finely serrate ; flowers in panicled spikes, 

 small nearly white, salverform, tube longer than the calyx; stamens 2, exserted; 

 pistil 1, style 1 ; fruit a capsule, oblong-ovate. 



Distribution. From western New England to Minnesota, Manitoba to 

 Nebraska and Kansas. 



Poisonous properties. The V. peregrina has been reported as poisonous. 

 The root of V '. virginica contains leptandrin. It is a violent emetic, cathartic, 

 and, according to Johnson, cannot be used with safety in medicine. 



3. Digitalis L. Foxglove 



Tall herbs, leaves alternate; large purple yellowish or white flowers borne 

 on 1-sided racemes ; calyx 5-parted ; corolla irregular ; tube contracted, upper 

 lip 2-cleft, lower lip 3-lobed, middle largest; stamens 4 didynamous; style slen- 

 der ; fruit a capsule ; seeds numerous, roughened. About 20 species in Asia 

 and Europe. 



Digitalis purpurea L. Purple Foxglove 



Biennial or annual pubescent herb with stout stem ; lower leaves ovate or 

 ovate-lanceolate, slender petioled, upper leaves smaller, sessile ; flowers borne 

 in long drooping racemes ; corolla spotted. 



Distribution. Native to Europe but widely naturalized in the Pacific North- 

 west 



Poisonous properties. The plant has long been used in medicine. For this 

 purpose the leaves of the second year's growth are collected. The active con- 

 stituents are such glucosides as digitoxin, C 34 H 50 O 10 . The most poisonous are 

 active, digitalin, C^H.-O,. . digitalein, an amorphous bitter substance soluble in 



o5 uo 14" 



water, digitonin, C 07 H 44 O 14 +H O and digitophyllin C 32 H 52 O 10 . The leaves 

 also contain luteolin which occurs in mignonette. 



In large doses digitalis is a gastro-intestinal irritant and in poisoning causes 

 nausea. It causes the pulse to become slower, fuller and stronger and more 

 regular. It causes stimulation of the heart muscles. In poisonous doses it is 

 rapid, weak and irregular. The respiratory centers are unaffected except by 

 toxic doses. The temperature is reduced by toxic doses. Dr. Winslow, in 

 speaking of the cumulative action of digitalis and the toxic action, says : 



Digitalis and strychnin are said to be cumulative in their action. Evidence is stronger in 

 the case of the former drug than in that of the latter. By cumulative action is meant sudden 

 transition from a therapeutic to a toxic effect. This may be due to three causes. 1. Tardy 

 absorption. 2. Increasing susceptibility. 3. Delayed elimination and accumulation of the 

 drug in the system. The cumulative action of digitalis is chiefly due to the latter cause. It 

 should never be administered in full medicinal doses uninterruptedly for any considerable 

 length of time. 



Toxicology. Poisoning may occur from large single doses within 3 to 10 hours of their 

 ingestion, and last for 16 or more hours with a fatal result; or may appear suddenly after the 

 administration for several days of large medicinal doses (cumulative action). A minimum 

 fatal dose for the horse is about I vi. of digitalis, or gr. i. ss. of Homolle's digitalin. For dogs, 



