ON  COLCHICIA. 
209 
dened  by  a  minute  quantity  of  sulphuric  acid,  completely  restores 
the  blue  color  to  the  liquid.  It  neutralizes  the  strongest  acids, 
and  forms  with  sulphuric  acid,  a  salt  which  I  think  is  evidently 
crystalline  when  examined  with  a  microscope.  These  properties 
give  it  an  unquestionable  right  to  be  classed  among  the  vegetable 
alkaloids. 
In  the  dose  of  l-10th  of  a  grain  colchicia  produced  a  purga- 
tive effect,  accompanied  by  a  great  deal  of  nausea  and  distress. 
A  decidedly  sedative  influence  on  the  circulation  was  experienced 
during  its  operation ;  the  pulse  being  reduced  from  eighty-six  to 
seventy  strokes  per  minute. 
The  following  list  of  tests  for  colchicia  has  been  prepared  with 
a  considerable  amount  of  care,  and  in  those  cases  in  which  a 
different  result  was  obtained  from  that  previously  published  by 
other  writers,  the  experiment  was  repeated  several  times,  in 
order  to  guard  against  error  from  accidental  causes. 
In  a  solution  in  distilled  water : — 
Tannin, — a  white  precipitate,  soluble  both  in  dilute  acids  and 
dilute  alkalies. 
Iodohydrargyrate  of  potassium, — a  white  precipitate. 
Aqueous  solution  of  iodine, — a  bulky  brown  precipitate. 
Chlorine  water, — no  immediate  effect,  but  after  a  few  seconds 
a  white  cloud  is  produced  ;  ammonia  added  dissolves  it  with  a  light 
brownish  color ;  a  small  portion  of  ferrocyanide  of  potassium 
added  before  the  ammonia  does  not  alter  the  effect. 
Red  oxide  of  mercury  dissolved  in  solution  of  iodide  of 
potassium, — an  immediate  white  precipitate,  soluble  in  excess. 
Ammonio-sulphate  of  copper, — a  greenish  color  ;  after  a  time 
a  light  green  precipitate  subsides. 
Sulphuric  acid, — a  clear  yellow  color. 
Nitric  acid, — a  clear  yellow  color. 
Both  neutral  and  subacetate  of  lead, — no  precipitate  or  colora- 
tion. 
Bichromate  of  potassa, — no  precipitate  or  coloration. 
In  a  solution  in  dilute  muriatic  acid  : — 
Ammonia, — a  white  precipitate,  soluble  in  excess. 
Terchloride  of  gold, — a  yellow  precipitate. 
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