ALKALOIDS 167 



pounds found dissolved in the cell-sap. Most of them are amido- 

 acids or simple derivatives of the latter. They are reserve-foods 

 chiefly present in the rhizomes, bulbs, tubers and roots of plants 

 and rarely in resting seeds. 



The most widely distributed representative is asparagine, which 

 is present in the parenchyma of almost all parts of plants : it is 

 more particularly abundant in the young shoots of asparagus, 

 sprouts and tubers of the potato and in seedlings of lupins, vetches 

 and other leguminous plants grown in the dark. 



Other common amido-acids are glutamine, betaine, leucine, and 

 tyrosine met with in the mangold, sugar-beet, turnip and other 

 roots. 



3. Alkaloids. — The alkaloids are organic compounds of a 

 basic nature ; most of them are poisonous and form the active 

 principle of many plants used as drugs. The most familiar 

 examples are morphine, obtained from the opium poppy, nicotine 

 from the tobacco plant, conine from hemlock, and strychnine 

 from Strychnos Nux vomica. 



