1 
28        DEPORTMENT  OF  ALKALOIDS  WITH  REAGENTS,  ETC. 
Nicotina  has  a  peculiar,  disagreeable,  somewhat  ethereal,  to- 
bacco-like odor,  an  acrid,  pungent  taste,  and  very  poisonous  pro- 
perties. Dropped  on  paper,  it  makes  a  transparent  stain,  which 
slowly  disappears  ;  it  turns  tumeric-paper  brown,  and  reddened 
litmus-paper  blue.  Concentrated  aqueous  solution  of  nicotina 
shows  these  reactions  more  distinctly  than  the  alkaloid  in  the 
pure  state. 
2.  Nicotina  has  the  character  of  a  pretty  strong  base  ;  it  pre- 
cipitates metallic  oxides  from  their  solutions,  and  forms  salts 
with  acids.  The  salts  of  nicotina  are  freely  soluble  in  water  and 
alcohol,  insoluble  in  ether ;  they  are' inodorous,  but  taste  strongly 
of  tobacco ;  part  of  them  are  crystallizable.  Their  solutions, 
when  distilled  with  solution  of  potassa,  give  a  distillate  contain- 
ing nico  ina.  By  neutralizing  this  with  oxalic  acid,  and  evapo- 
rating, oxalate  of  nicotina  is  produced,  which  may  be  freed  from 
any  admixture  of  oxalate  of  ammonia,  by  means  of  spirit  of  wine, 
in  which  the  former  salt  is  soluble,  the  latter  insoluble. 
.  If  an  aqueous  solution  of  nicotina,  or  a  solution  of  salt  of 
nicotina  mixed  with  solution  of  soda  or  potassa,  is  shaken  with 
ether,  the  nicotina  is  dissolved  by  the  ether  ;  if  the  latter  is  then 
allowed  to  evaporate  on  a  watch-glass,  the  nicotina  remains  be- 
hind in  drops  and  streaks ;  on  warming  the  watch-glass,  it  vola- 
tilizes in  white  fumes  of  strong  odor. 
4.  Bichloride  of  platinum  produces  in  aqueous  solutions  of 
nicotina  whitish-yellow  flocculent  precipitates.  On  heating  the 
fluid  containing  the  precipitate,  the  latter  dissolves,  but  upon 
continued  application  of  heat  it  very  speedily  separates  again  in 
form  of  an  orange-yellow,  crystalline,  heavy  powder,  which, 
under  the  microscope,  appears  to  be  composed  of  roundish  crys- 
talline grains.  If  a  rather  dilute  solution  of  nicotina,  supersatu- 
rated with  hydrochloric  acid,  is  mixed  with  bichloride  of  plati- 
num, the  fluid  at  first  remains  clear;  after  some  time,  however, 
the  double  salt  separates  in  small  crystals  (oblique,  four-sided 
prisms),  clearly  discernible  wfth  the  naked  eye. 
5.  Terchloride  of  gold  produces  a  reddish-yellow  flocculent 
precipitate,  sparingly  soluble  in  hydrochloric  acid. 
6.  Solution  of  iodine  in  iodide  of  potassium  and  water,  when 
added  in  small  quantity  to  an  aqueous  solution  of  nicotina,  pro- 
