504  DOES  NICOTINA  EXIST  IN  GREEN  TOBACCO? 
renewing  the  liquid  as  it  evaporated,  when  the  whole  was  thrown 
on  a  displacement  filter,  and  the  seed  exhausted.  The  liquid 
was  evaporated  to  four  fluid  ounces,  mixed  with  a  drachm  of 
magnesia,  and  agitated  at  intervals  for  12  hours,  when  it  was 
filtered.  Previously  to  the  addition  of  the  magnesia  the  liquid 
had  but  little  odor  or  color  :  after  the  action  of  that  base  it  had 
a  brown  color  and  decided  unpleasant  odor,  similar  to  that  in 
the  preceding  experiment.  This  liquid  was  carefully  distilled 
until  three-fourths  of  its  bulk  had  passed.  The  distillate  was 
decidedly  alkaline  to  test  paper.  It  was  now  carefully  tested 
for  nicotina,  with  the  following  results: 
1.  It  was  not  precipitated  by  tannic  acid. 
2.  Corrosive  sublimate  caused  a  white  precipitate. 
3.  Acetate  of  lead  occasioned  a  white  precipitate. 
4.  Sesquichloride  of  iron,  a  brown  flocculence. 
5.  Terchloride  of  gold,  no  precipitate  at  first,  but  by  standing, 
a  brown  one. 
6.  Aqueous  solution  of  iodine,  no  precipitate,  and  instantly 
decolorized. 
7.  Ioduretted  iodide  of  potassium,  at  once  decolorized,  and 
no  precipitate. 
8.  Sulphate  of  zinc,  a  white  precipitate. 
9.  Chloride  of  cobalt,  a  pink  flocculent  precipitate. 
It  is  evident,  by  comparing  this  series  with  that  of  nicotina 
in  the  sequel,  that  the  alkalinity  of  the  distillate  from  the  seeds 
is  not  due  to  that  alkaloid,  and,  as  the  proportion  of  seeds  was 
far  greater  than  in  any  of  the  experiments  with  the  leaves  ;  it 
follows  that  the  yield  of  nicotina,  had  it  been  present,  should 
have  been  greater ;  whereas  the  liquid  was  not  as  alkaline  as 
that  from  the  green  leaves. 
The  reactions  above  indicated  are,  many  of  them,  those  of 
ammonia,  but  that  with  cobalt  is  different,  and  the  nature  of 
the  active  principle  of  the  seeds,  or  indeed  its  real  activity,  remains 
undetermined.  It  would  have  been  well  to  have  tried  some 
physiological  experiments  with  tobacco  seed,  to  see  if  they  are 
more  active  than  the  leaves.  If  they  are  more  active,  and 
possess  the  same  acro-narcotic  power,  then  it  would  be  well  to 
seek  for  their  active  principle  in  another  direction  than  that  of 
