Am.  Jour.  Pharm.  ) 
March  1, 1871.  j 
Chloral, 
115 
hydrate  of  chloral  should  contain  64*35  per  cent,  of  chlorine.  M. 
Personne  found  that  the  preparation  he  had  made  contained  63*79 
per  cent.,  whilst  a  sample  of  that  made  by  M.  Roussin  yielded  only 
54*89  per  cent.  Following  this  indication,  Personne  endeavored  to 
ascertain  by  experiments  whether  the  hydrate  of  chloral  prepared  by 
Roussin  did,  or  did  not,  contain  alcohol.  The  results  were  very  satis- 
factory in  proving  the  presence  of  this  compound.  Further,  by  com- 
bining anhydrous  chloral  and  absolute  alcohol  in  proper  proportions, 
Personne  was  enabled  to  prepare  synthetically  a  substance  having 
properties  entirely  similar  to  those  of  the  supposed  hydrate  of  chloral 
prepared  by  Roussin. 
It  is  this  preparation,  alcoholate  of  chloral,  represented  by  C2CI3HO 
-f  CgHgO,  that  we  meet  with  in  commerce,  also  hydrated  alcoholate 
of  chloral,  which  are  not  to  be  trusted  as  therapeutic  agents  accord- 
ing to  the  system  laid  down  by  Liebreich. 
At  a  meeting  of  the  Pharmaceutical  Society,  Mr.  John  Williams 
suggested  that  an  alkaline  reagent  would  show  the  percentage  of  chlo- 
roform the  chloral  preparation  would  produce.  Mr.  Charles  Umney 
has  also  made  some  very  valuable  experiments,  and  instituted  what  is 
now  known  to  pharmacists  as  "the  ammonia  process"  for  testing 
hydrate  of  chloral.  The  mode  of  operating,  and  the  results  of  his 
experiments,  are  published  in  the  Pharmaceutical  Journal. 
I  find  that  hydrate  of  chloral  is  insoluble  in  cold  chloroform,  tetra- 
chloride of  carbon,  turpentine  and  bisulphide  of  carbon,  but  on  the 
application  of  heat,  solution  is  elfected.  The  hydrate  is,  however, 
perfectly  soluble  in  cold  water,  ether  (*735)  and  absolute  alcohol 
(•805) ;  after  the  application  of  heat,  and  upon  cooling,  the  hydrate 
separates  in  beautiful  crystals,  generally  needles,  but  from  bisulphide 
of  carbon  in  prisms.  True  hydrate  of  chloral  is  not  acted  upon  by 
nitrate  of  silver  or  by  acids. 
Alcoholate  of  chloral  is  perfectly  soluble  in  chloroform,  ether,  tetra- 
chloride of  carbon,  absolute  alcohol,  turpentine,  and  bisulphide  of 
carbon,  and  upon  heating  does  not  present  any  change,  nor  can  I 
produce  crystals  from  these  alcoholic  solutions.  Why,  I  do  not  quite 
understand.  In  cold  water  alcoholate  of  chloral  is  nearly  insoluble ; 
and  I  venture  to  suggest  this  as  a  simple  test  for  these  two  forms  of 
chloral  compound. 
If  twenty  grains  of  the  chloral  compound  is  soluble  in  thirty  minims 
of  cold  chloroform,  it  is  not  a  hydrate;  on  the  other  hand,  if  the  same 
