102 PASTORAL AND AGRICULTURAL BOTANY 



Potato (Soianum tuber osum). Although the potato plant is con- 

 sidered one of the principal food plants of the human race, yet there are 

 parts of the plant which are poisonous, and there are conditions in which 

 the tubers develop poisonous properties. The tops of the plants stems 

 and leaves are poisonous containing the active principle. Even the tubers 

 which are eaten with impunity by the majority of people may be injurious 

 to some persons with a susceptible idiosyncrasy. Again when tubers are 

 stored in a damp cellar to which sunlight has access, they may develop a 

 green color. Such greened tubers and the tube-rs from which young shoots 

 have sprung develop the poisonous properties of the tops and have been 

 the cause of accidental poisoning. Macfadyen has shown that old 

 sprouted potatoes, even after boiling, are poisonous to horses. Two cows 

 became ill after eating potato parings, as they contain more of the toxic 

 principle than the "flesh." 



Poisonous Substances. The three above mentioned species of the 

 genus Soianum, as well, as other species of the genus contain an alkaloid 

 solanin (C52H93NOig) having a hot, bitter taste. Soianum [dulcamara 

 the bittersweet contains in addition dulcamin, which gives it its peculiar 

 bitter-sweet taste. The black night shade contains also solanidin (C4o- 

 H 6 iNO 2 ) with strong basic properties. 



Sneeze-weed (Helenium autumnale). A perennial herb with smooth, 

 or puberulent, stem 6 to 18 decimenters high. The leaves are firm, 

 sharp-pointed with decurrent, sessile bases. The heads are numerous 

 3-5 centimeters broad borne on long peduncles. The ray flowers are 

 blight-yellow, 3-cleft and drooping, ten to eighteen in number. The 

 disk-flowers are perfect, fertile and yellow in color. The achenes are 

 pubescent on the angles, while the pappus scales are ovate, sharp-pointed, 

 or toothed. The swamp sunflower, or yellow star, is found in swamps 

 and wet meadows from Quebec to Connecticut, Florida, South Dakota, 

 Kansas and Alabama. It occurs in the Rocky mountains from Wyom- 

 ing to Montana in a variety gran diflorum. It is in flower from August until 

 October. Its common name refers to the sneezing of which it produces, 

 a fact known to the Winnebago Indians, who used it for that purpose. 



Symptoms. Sheep, cattle and horses, that are unfamiliar with the 

 plant which is more or less bitter, acrid and pungent, are often poisoned 

 by it when driven to pastures where it is abundant. As a rule, because 

 of the above-mentioned qualities, animals avoid it, but they sometimes 

 acquire a taste for it and are quickly killed by eating it in large amounts. 



