154 
Calomel. 
\  Am.  Jour.  Pharm, 
X    April  1,  1871. 
The  odor  of  the  benzine  disappears  when  the  solution  is  added  in 
this  way.  It  is  quite  important  to  avoid  an  excess  of  heat,  and  hence 
the  water-bath  is  recommended. 
Liquid  rubber  will  be  found  to  act  admirably  in  all  plasters  which 
may  be  made  to  keep  through  the  summer. 
CALOMEL. 
By  Oscar  Oldberg,  Professor  of  Pharmacy,  Washington,  D.  0. 
It  is  a  rule,  generally  adopted  by  compilers  and  revisers  of  phar- 
macopoeias and  piirirraaceutical  formularies,  to  select,  for  officinal 
works,  such  formuli^e  and  processes  as  will  be  most  practicable  to  the 
pharmacist  proper.  Pharmacopoeias  are  not  written  for  wholesale 
manufacturers.  For  such  preparations  as  can  bt3  more  profitably  pre- 
pared on  a  large  scale,  no  officinal  formul^B  are,  therefore,  given  in 
many  pharmacopoeias  ;  and  out  of  two  processes,  which  both  give  an- 
equally  good  product,  we  should  certainly  prefer  the  one  which  is 
most  economical  and  least  troublesome. 
I  do  not  believe  that  our  national  pharmacopoeia  has  done  wisely  in 
the  selection  of  its  formula  for  the  preparation  of  tlie  mild  chloride  of 
mercury.  The  process  in  question  is  too  troublesome  to  be  adopted, 
even  to  a  small  extent,  by  the  apothecaries  ;  and,  besides,  there  exists 
another  formula  which  is  more  convenient,  while,  at  the  same  time,  it 
gives  also  a  more  beautiful  product.  The  process  of  the  U.  S.  Ph. 
is  fan)iliar  to  us  all.  The  other  method  is  officinal  in  several  foreign 
pharmacopoeias,  among  which  may  be  mentioned  those  of  Sweden  and 
of  Saxony.  The  U.  S.  Dispensatory  seems,  however,  to  ignore  it 
altogether,  though  it  is  nearly  a  century  old,  and  has  been  consider- 
ably improved  since  first  brought  into  notice  by  Scheele.  It  directs 
the  preparation  to  be  made  by  precipitation. 
Professor  Wood,  after  speaking  of  Wohler's  Avet  process,  adds: 
"This  form  of  calomel  is. of  doubtful  utility  ;  and,  when  obtained  by 
Prof.  Wohler's  process,  it  is  a  crystalline  powder,  which  is  a  fatal 
objection  to  it."  Is  not  the  sublimated  calomel  made  according  to 
officinal  directions  of  the  U.  S.  Ph.  also  crystalline,  and  as  fatally 
objectionable  ?  The  products  of  both  these  formulae  must  undergo  a 
tedious  process  of  levigation  and  elutrition,  to  enable  us  to  reduce 
them  to  an  impalpable  powder,  and  free  them  from  the  contamination 
of  bichloride. 
