446 
Notes  on  Chloral. 
(  Am.  Jour.  Pharm. 
\    Oct.  1, 1871. 
NOTES  ON  CHLORAL. 
By  Rob.  F.  Fairthorne. 
Hydrate  of  chloral  having  become  so  popular  as  a  remedy  lately,  I 
thought  that  a  description  of  its  physical  characteristics  and  its  be- 
havior when  brought  in  contact  with  other  substances  might  prove 
interesting. 
As  found  in  the  shops  of  Philadelphia  it  appears  in  three  different 
conditions.  That  of  German  manufacture  in  compressed,  flattened 
masses  of  various  sizes,  which  have  (when  freshly  broken)  a  shining 
fracture,  the  facets  of  the  crystals  of  which  they  are  composed,  glis- 
tening, and  giving  to  them  considerable  resemblance  to  pieces  of  sper- 
maceti. Another  form  it  is  found  in,  is  in  tabular  crystals  having  a 
rhomboidal  construction.  The  American  hydrate,  however,  appears 
generally  to  consist  of  loose  acicular  crystals,  which,  when  recently 
prepared,  are  almost  transparent,  but  which  after  a  while  sometimes 
become  opaque ;  their  solubility  in  water  being  much  reduced  after 
this  alteration  has  occurred.  May  not  this  be  due  to  the  same  cause 
that  produces  a  change  in  anhydrous  chloral,  which  is  occasionally 
converted  into  a  hard  opaque  insoluble  substance  ?  Its  odor  is  at 
the  same  time  altered  to  some  extent,  becoming  more  pungent  and 
irritating  to  the  nostrils.  I  think  that  probably  the  hydrate  or  its 
vapor  becomes  partially  dehydrated.  It  may  possibly  be  produced 
by  the  action  of  light,  as  the  vapor  of  alcohol,  if  exposed  to  sunlight 
in  the  presence  of  chloral,  explodes.  Chloroform  is  also  affected  by 
long  exposure  to  light  and  air,  chlorine  and  hydrochloric  acid  being 
developed. 
When  a  little  of  this  substance  is  placed  on  the  glass  slide  of  a 
microscope  and  melted  by  the  application  of  heat,  upon  cooling  it 
will  be  found  that  crystals  have  been  formed.  These,  when  magni- 
fied, present  a  very  beautiful  appearance,  and  will  be  observed  to 
have  assumed  two  distinct  forms  ;  one  portion  appearing  as  rhom- 
boidal plates  and  the  other  (by  far  the  greater  part)  as  transparent 
acicular  crystals,  arranged  in  tufts  of  radiating  prisms,  the  termina- 
tions of  which  are  divided  into  feathery  lines. 
Anhydrous  chloral  has  nearly  the  same  specific  gravity  as  chloro- 
form, being  1*500,  that  of  chloroform  1*495.  It  has  a  strong  affinity 
for  water,  with  which  it  combines,  forming  the  crystalline  substance 
just  described.  It  unites  also  with  alcohol  a  compound  resulting 
that  resembles  the  hydrate  in  appearance. 
