Am.  lour.  Pharm.  > 
Mar.,  1879.  / 
Cinchona  Alkaloids. 
2.  The  relative  strength  of  the  sulphocyanide  of  potassium  solution 
and  the  alkaloidal  solution,  as  far  as  practicable,  must  not  vary  after 
it  has  been  once  decided  upon. 
3.  The  alkaloidal  solutions  must  be  saturated  solutions  of  the  respec- 
tive sulphates  in  water  at  ordinary  temperature.  They  may  be  obtained 
by  digesting  1  part  of  the  sulphate  with  10  parts  of  water,  at 
500  to  6o°C.  for  a  few  minutes,  and  when  the  mass  has  acquired  the 
ordinary  temperature  filtering  the  solution  ;  the  filtrate  must  not  have 
the  property  of  crystallizing  independently  when  the  microscopic  test  is 
applied. 
4.  Observations  of  the  reactions  must  be  repeated  until  no  change 
is  apparent.  The  time  usually  required  for  each  reaction  is  only  a 
few  minutes,  with  a  few  exceptions,  where  an  hour  and  more  is  needed. 
My  observations,  described  in  the  following,  will  embrace  only  the 
sulphates  of  quinia,  cinchonidia,  quinidia,  cinchonia  and  homo-cincho- 
nidia;  the  latter  is  included  on  account  of  its  frequent  presence  in 
cinchonidia,  and  sometimes  even  in  sulphate  of  quinia.  Of  Drygin's  new 
alkaloid  cinchonichia,  asserted  to  be  present  in  sulphate  of  quinia  to  the 
extent  of  6  per  cent.,  no  further  notice  was  taken,  as  I  consider  it 
insufficiently  examined  cinchonidia. 
Sulphate  of  Quinia.— Only  absolute  pure  sulphate  was  employed. 
Special  mention  is  made  of  this  as  the  commercial  article  prepared 
according  to  the  various  pharmacopoeias  cannot  be  always  depended  on. 
For  instance,  the  British  Pharmacopoeia  allows  sulphate  of  quinia  to  pass 
as  pure,  though  it  is  liable  to  contain  about  20  per  cent,  cinchonidia 
sulphate.  The  absence  of  other  cinchona  alkaloids  from  sulphate  of 
quinia  may  be  determined  by  digesting  2  grams  of  the  latter  for  a  short 
time  with  10  times  its  weight  of  water  at  500  to  6o°C,  shaking  the 
cooled  and  filtered  solution,  after  precipitation,  with  ether,  and  slowly 
evaporating  the  latter.  If  the  sulphate  was  pure,  the  residue  is  entirely 
amorphous.  Pure  and  unefHoresced  sulphate  of  quinia  (with  8H20)  is 
soluble  at  20°C.  in  about  600  parts,  and  sulphocyanide  of  quinia  in 
562  parts  of  water;  the  latter  combination  being  more  soluble  than  the 
former,  it  seems  reasonable  that  the  sulphate  has  not  a  tendency  to  be 
readily  converted  into  sulphocyanide.  Nevertheless,  sulphocyanide  of  qui- 
nia is  formed  when  the  two  solutions  are  brought  in  contact,  and  this  is 
due  to  sulphocyanide  of  quinia  being  less  soluble  in  solution  of  sulpho- 
cyanide of  potassium  than  in  pure  water  (contrary  to  Schrage's  state- 
