THE VEGETABLE BASES 153 



Choline and betaine are non-toxic; while muscarine and neu- 

 rine are violent poisons. 



Choline and muscarine occur in certain toadstools. Betaine 

 and choline often occur together in the germs of many plants. 

 Betaine is found in the beet root and the tubers of Jerusalem 

 artichoke. Choline occurs alone in the seeds and fruits of many 

 plants, sometimes as the free amine, but more often as a constit- 

 uent of lecithin (see page 141). 



Phenyl derivatives of simple amines are sometimes found in 



plants. Hydroxyphenylethyl amine, HO<^ yCH2 CH2 NH2, 



found in ergot, and hordeine, H0<^ ^>CH 2 -CH 2 -N-CCHs^, 



found in barley, are examples. The former has marked medicinal 

 properties,. 



There is no known physiological use for these simple amines in 

 plants. By some investigators, they are regarded as intermediate 

 products in the synthesis or decomposition of proteins; but it 

 would seem that if this were a normal procedure, these amines 

 would occur in varying proportions in all plants, under different 

 conditions of metabolism, instead of in practically constant propor- 

 tions in only a few species, as they do. 



ALKALOIDS 



These are a group of strong vegetable bases whose nitrogen 

 atom is a part of a closed-ring arrangement. 



As a rule, alkaloids are colorless, crystalline solids, although a 

 few are liquids at ordinary temperatures. They are generally 

 insoluble in water, but easily soluble in organic solvents. Being 

 strong bases, they readily form salts with acids, and these salts are 

 usually readily soluble in water. 



Alkaloids are usually odorless; although nicotine, coniine, and 

 a few others, have strong, characteristic odors. Most of them 

 have a bitter taste, and many of them have marked physiological 

 effects upon animal organisms, so that they are extensively used 

 as narcotics, stimulants, or for other medicinal purposes. 



Most of the alkaloids contain asymmetric carbon atoms and 

 are, therefore, optically active, usually levorotatory, although a 

 few are dextrorotatory. 



