GLEANINGS  FROM  THE  GERMAN  JOURNALS.  421 
water,  to  which  is  added  a  few  drops  of  concentrated  sulphuric 
acid.  Upon  heating  this  mixture  the  sugar  becomes  carbonized, 
and  when  applied  to  the  paper  leaves  a  coating  of  carbon  which 
cannot  be  washed  off.  This  stain  is  rendered  more  permanent 
by  the  decomposing  action  of  the  acid  itself  upon  the  paper,  and 
thus  made,  it  resists  the  action  of  chemical  agents.  The  paper 
should,  after  drying,  be  passed  through  a  weak  alkaline  solution 
to  remove  excess  of  acid  Breslauer  Gewerbebl.  ffl  Jahrb.  Ph. 
xx.  330.  * 
Benzine  as  an  Insecticide. — A  mixture  of  10  parts  benzine, 
5  parts  soap  and  85  water,  has  been  very  successfully  used  by 
Gille,  to  destroy  the  parasites  which  infest  dogs.  It  has  also 
been  used  with  good  results  in  veterinary  practice,  as  an  appli- 
cation in  certain  diseases  of  the  skin ;  and  thus  diluted,  is  found 
to  answer  better  than  when  used  pure. — Bull,  de  Ph.  de  Brux. 
K  Jahrb.  Ph.  xxi.  36. 
Preservation  of  Lemonade. — The  spontaneous  change  which 
this  liquid  undergoes,  and  the  early  deposition  of  a  granular 
salt,  when  prepared  in  a  concentrated  form,  prevents  its  being 
kept  longer  than  a  few  days.  Ladi,  has  suggested  the  employ- 
ment of  the  sulphite  of  magnesia  as  a  means  of  preserving  it  for 
a  longer  time  ;  the  gradual  oxidation  by  which  it  becomes  con- 
verted into  the  sulphate  of  magnesia,  appearing  to  prevent 
the  alteration.  A  very  small  quantity  is  said  to  be  sufficient. 
Schweiz.  Zeitschf.  Ph.    N.  Jahrb.  xxi.  39. 
Preservation  of  Fresh  Meat,  $e  Several  specimens  of  fresh 
meat  and  fish,  preserved  by  the  following  process,  were  exhibi- 
ted during  the  late  London  Exhibition,  by  R.  Jones  and  F.  Tre- 
vithick,  of  London,  and  retained  during  the  whole  of  the  exhi- 
bition their  fresh  appearance.  The  uncooked  meat  is  placed  in 
a  strong  tin  vessel,  from  which  the  air  is  exhausted  by  means 
of  an  air  pump.  A  small  quantity  of  sulphurous  acid  is  then 
introduced  which  is  rapidly  absorbed  by  the  meat,  when  the 
vessel  is  filled  with  pure  nitrogen  gas,  and  hermetrically  sealed. 
(Carbonic  acid,  which  is  more  easily  prepared,  might  perhaps 
answer  as  well.)    Dr.  A.  Geyger,  in  N.  Jahrb.  Ph.  xx.  215. 
Estimation  of  Copper  in  vegetable  extracts,  food,  $c. — Hager 
