CHARCOAL  AS  A  MEDIUM  OF  INHALATION. 
431 
change  is  best  observed  by  means  of  the  saccharometer.  The 
dextrogyration  decreased  most  rapidly  with  a  solution  of  pure 
sugar,  and  was  less  when  the  solution  contained  some  lime, 
which  appears  to  retard  the  change.  The  rapidity  of  the  change 
is  increased  by  heat.  Glucose  or  gum  do  not,  under  the  same 
circumstances,  suffer  any  alteration.  The  presence  of  organic 
acids  was  found  to  exert  but  little  influence  upon  the  alteration 
of  sugar. 
From  these  observations  the  author  concludes — 1.  That  the 
roots  of  beet  will  yield  less  crystallizable  sugar  the  longer  they 
are  kept;  2.  That  a  diminution  of  crystallizable  sugar  must 
result  from  the  method  of  drying  the  roots ;  3.  That  the  per- 
centage of  sugar  in  old  syrups  cannot  be  ascertained  by  means 
of  the  optical  test ;  4.  The  brown  color  produced  by  heating 
syrup  with  potash  cannot  alone  be  taken  as  an  indication  of  the 
presence  of  glucose,  since  the  uncrystaliized  cane  sugar  presents 
the  same  reaction. 
When  the  cane  sugar  in  syrup  which  is  old,  or  which  contains 
gum,  is  to  be  estimated,  this  must  be  done  by  evaporation  over 
lime  or  sulphuric  acid.  The  cane  sugar  then  crystallizes  out, 
and  the  point  at  which  the  gum  begins  to  dry  may  be  very  well 
observed.  When  the  syrup  contains  glucose  instead  of  cane 
sugar,  no  crystals,  or  very  few,  are  obtained.—  Pharm.  Jour. 
July,  1855.* 
CHARCOAL  AS  A  MEDIUM  OF  INHALATION. 
By  Mr.  Stephen  Darby. 
The  explanation  of  the  real  action  of  charcoal,  in  contact  with 
effluvia,  for  which  we  are  indebted  to  Dr.  Stenhouse,  and  the 
application  of  it  in  many  ways  for  sanitary  purposes,  as  recom- 
mended by  him,  has  naturally  given  rise  to  many  suggestions 
for  the  use  of  this  most  important  agent. 
[We  observed  this  spontaneous  change  of  cane  into  grape  sugar,  in  a 
yial  of  simple  syrup  kept  in  our  cabinet  during  six  years,  when  using  it  in 
illustrating  the  reaction  of  potash  on  the  two  sugars.  The  coloration  of 
the  liquid  in  the  cane  sugar  experiment  led  us  to  infer  and  believe  this 
change  had  occurred. —  Ed.  Am.  Journ.  Pharm.] 
