464 SCIENCE PROGRESS 



melts at 1 13 . In this case also the labile isomer has a mydriatic 

 action, while the stable isomer lacks that property. 

 The actions of the two antipodic forms of nicotine : 



N-CH 3 CH 



CH, CH CH CH 



I I II I 



CH, — CH, CH CH 



\ // 



CH 



have been studied by Mayor, 1 who found that the lsevo form was 

 twice as poisonous as the other. When dextro nicotine is 

 injected no pain is felt ; but when the laevo isomer is used it 

 produces both pain and excitation. The laevo antipode causes 

 paralysis, spasms, retardation of the action of the heart, and 

 finally death by the cessation of respiration ; while the same 

 dose of dextro nicotine produces only a strong shivering fit, 

 which soon passes off. 



Only one or two other cases need be mentioned in this 

 division of the subject. Albertoni 2 has shown that the dextro- 

 rotatory compound cinchonine differs in action from its lasvo- 

 rotatory isomer cinchonidine. The latter has a slower action, 

 requires a larger dose to produce the same effect as the dextro 

 isomer, gives rise to vomiting, and has a marked tendency to 

 cause spasms. Quinine and quinidine, which are also optical 

 isomers, differ in physiological action as well, quinidine having 

 no narcotic properties, though showing the febrifugial action 

 of quinine. 



Coniine has the structure : 



CH, 

 / \ 



CH, CH, 



I I 

 CH> CH . C3H7 



\ / 

 NH 



and as it contains an asymmetric carbon atom it occurs in active 

 and racemic forms. Ladenburg and Falk 3 compared the action 

 of the dextro antipode with that of the racemic form, but were 

 unable to detect any difference between the two effects. 



1 Mayor, Ber., 38, 597 (1905). 



2 Albertoni, Archiv exp. Path. u. Pharmak., 15, 272. 



3 Ladenburg and Falk, Annalen d. C/tem., 247, 83 (1888). 



