434    MANUFACTURE,  IMPURITIES  AND  TESTS  OF  CHLOROFORM. 
seven  charges  are  worked  off  from  the  apparatus  each  day  during 
the  process. 
The  chlorinated  lime  or  "bleaching  powder,"  for  this  process, 
reacts  in  virtue  of,  and  in  proportion  to  the  hypochlorite  of  lime 
it  contains ;  and  the  chlorine  of  this  hypochlorite,  which  is  the 
ultimate  effective  reagent,  varies  in  general  between  twenty-four 
and  thirty  per  cent,  of  the  whole  weight.  Occasionally  there 
is  as  much  as  three  or  four  per  cent,  variation  in  the  proportion 
of  chlorine  in  the  contents  of  the  same  cask,  through  long  keep- 
ing, carelessness  or  design  in  the  manufacturing,  the  chlorine 
being  the  expensive  element. 
The  alcohol  for  this  process  should  be  highly  rectified,  because 
in  this  rectification,  up  to  ninety-one  per  cent,  for  instance,  it 
must  necessarily  be  freed  to  a  great  extent  from  the  grain  oils 
and  other  impurities  whose  reaction  with  chlorine  produce 
deleterious  compounds. 
Manufacturers  on  the  large  scale,  who  too  often  take  purity  of 
product  into  their  scheme  as  collateral,  use  in  this  process 
whiskey,  or  spirits  that  have  been  recovered  from  other  processes, 
as  extraction  of  alkaloids,  &c,  which  are  cheap,  but  are  of  course 
filled  with  foreign  substances,  whose  reaction,  with  chlorine, 
cannot  be  prevented  nor  determined.  In  this  way,  notwith- 
standing the  assertions  that  have  been  made  to  the  contrary, 
there  can  be  little  doubt  that  many  deleterious  compounds  are 
produced  in  the  process,  and  pass  with  the  chloroform  (no  lime 
purifier  being  used)  not  only  into  the  market  where  the  profits 
are  realized,  but  also  into  the  lungs  of  the  patients,  and  by  re- 
flection affect  injuriously  the  credit  and  character  of  the  medical 
profession. 
These  deleterious  compounds  are  exceedingly  subtile,  and  like 
many  hydrocarbon  compounds,  are  often  produced  in  groups. 
From  the  looseness  of  their  affinities,  they  are  so  delicate  and  so 
easily  modified  in  character  and  composition,  that  they  may  be 
more  or  less  noxious  in  a  proportion  that  it  is  impossible  to  de- 
termine, even  at  different  ages,  of  any  given  sample.  From  these 
circumstances  it  happens  that  they  are  very  difficult  to  separate 
or  determine ;  but  fortunately  they  are  not  difficult  to  detect. 
If  they  ever  occur  in  chloroform  made  properly,  and  from  good 
materials,  it  must  be  very  rarely,  and  in  proportions  too  minnte 
