^  juS;  mL }         Crystallizatio7i  of  Camphor,  269 
camphor,  although  not  the  most  practicable,  is  undoubtedly  the  method 
by  precipitation.  The  trituration  with  small  quantities  of  chloroform, 
ether,  benzine,  and  naphtha^  has  been  proposed ;  but  none  of  these 
substances  possess  any  advantages  over  alcohol,  which  even  still  is 
preferable  to  all.  There  is  no  difficulty  whatever  in  pulverizing 
camphor  ;  the  object  is  to  retain  it  so. 
For  this  purpose  it  has  been  suggested  to  triturate  the  camphor 
with  small  quantities  of  magnesium  carbonate.  If  this  management 
insured  the  pulverulent  state  indefinitely,  the  magnesium  would  often 
be  objectionable.  The  writer  has  not  tested  the  process,  but  was  in- 
formed by  good  authority  that  it  is  not  satisfactory ;  a  similar  result 
is  experienced  by  precipitating  the  camphor  with  water  from  an  alco- 
holic solution,  holding  the  magnesium  carbonate  in  suspension.  Other 
dry  substances,  as  starch,  for  instance,  have  been  used  with  equally 
indilFerent  success.  The  writer,  feeling  the  necessity  of  some  alter- 
native, and  basing  his  theory  of  this  crystallization  upon  the  volatility 
of  camphor,  applied  an  etherial  solution  of  resin  with  a  view  of  coat- 
ing the  particles  with  a  deposit  of  resin.  The  experiment,  however, 
yielded  a  negative  result.  The  writer,  assuming  then  that  a  non- 
volatile solvent  might  retard  the  crystallization,  employed  a  small 
proportion  of  fixed  oil — preferably  castor  oil.  This  addition  is  en- 
tirely unobjectionable,  and  although  it  does  not  strictly  meet  the  most 
sanguine  expectation  of  preventing  crystallization,  it  yet  modifies  this 
tendency  to  such  a  degree  that  after  a  long  trial  the  writer  is  so 
thoroughly  satisfied  with  its  peculiar  advantages  that  the  complete 
success  of  the  experiment  would  have  been  scarcely  hailed  with  more 
delight.  The  proportion  of  castor  oil  employed  is  about  one  part  in 
thirty  of  camphor,  or  even  less.  It  is  added,  together  with  the  alco- 
hol, to  the  camphor,  and  the  whole  triturated  to  the  proper  degree  of 
fineness.  The  great  advantage  rests  in  the  fact  that  the  crystals  of 
camphor  subsequently  formed  are  exceedingly  minute,  and  the  oil 
entirely  removes  the  very  disagreeable  adhesiveness  and  tenacity  of 
the  camphor,  which  becomes  so  troublesome  during  the  trituration  of 
pure  camphor.  Camphor  containing  the  oil  can  be  triturated  in 
large  or  small  quantities,  without  in  the  least  clogging  the  mortar  or 
pestle.  The  powder,  after  keeping  even  a  long  time,  mixes  perfectly 
and  with  facility  with  all  the  ordinary  ingredients  with  which  it  is 
usually  combined  in  prescriptions.  The  peculiar  gumminess  has  been 
perfectly  removed  by  the  intervention  of  the  oil. 
