AmMTa0ru:\87hsarm*}  The  Origin  of  Tragacanth.  127 
ride  of  iron  by  washing  with  distilled  water,  and  redissolve,  by  mace- 
rating for  two  days,  the  precipitate  in  half  a  liter  of  distilled  water, 
previously  acidulated  with  12  drops  of  pure  hydrochloric  acid. 
Numerous  experiments  made  by  me  proved  that  only  in  the  follow- 
ing manner,  by  carefully  avoiding  an  excess  of  hydrochloric  acid  in 
the  ferric  chloride,  a  preparation  may  be  obtained  answering  to  the 
-description  given  by  Dr.  Triese.  It  is  well  known  that  the  officinal 
liquor  nearly  always  contains  an  excess  of  hydrochloric  acid,  which  in 
the  preparation  of  ferrum  albuminatum  will  cause  a  solution  of  the 
greater  portion  of  the  precipitate,  which  will  then  necessarily  go  to 
waste  by  washing.  This  loss  is  avoided  by  using  a  neutral  ferric  chlo- 
ride obtained  in  the  following  manner :  Dissolve  6  parts  of  dry  ferric 
chloride  obtained  by  evaporating  the  officinal  liq.  ferri  sesquichlorati,  in 
10  parts  of  distilled  water,  filter  and  mix  the  filtrate  intimately  with  20 
parts  of  the  white  of  eggs  ;  place  the  brownish-yellow  magma  on  a 
moistened  strainer,  press  well  with  the  hands  and  repeat  it  several 
times,  after  the  addition  of  a  little  distilled  water,  until  the  excess  of 
chloride  of  iron  is  removed.  Dissolve  the  residue  in  J-  liter  of  distilled 
water,  acidulated  with  12  drops  of  hydrochloric  acid,  by  macerating 
for  one  or  two  days,  and  filter. 
Dr.  Triese  administers  this  preparation  in  chlorosis  without  the  addi- 
tion of  phosphorated  ether  ;  it  must,  then,  always  be  freshly  prepared. 
As  a  remedy  for  rhachitis  he  prescribes  an  addition  of  12  drops  of  a 
solution  of  0*05  grm.  phosphorus  in  30  grm.  of  ether  to  250  grm.  of 
the  iron  albuminate  solution,  which  keeps  the  latter  unaltered  for  at 
least  six  weeks,  and  permits  it  to  be  kept  on  hand  for  that  length  of 
time. 
ON  THE  ORIGIN  OF  TRAGACANTH.1 
By  M.  Giraud. 
The  formation  of  gum  in  plants  seems  to  depend  upon  a  peculiar 
morbid  condition,  the  main  phases  of  which  were  investigated  and 
described  by  Trecul  in  i860.  Although  he  studied  the  formation  of  gum 
only  in  the  Rosaceae,  it  has  been  taken  for  granted  that  a  similar  process 
yields  the  gum  of  the  Acaciae,  which,  being  an  article  of  commerce, 
is  of  much  greater  importance.  The  gum-disease  is  caused  by  a  full- 
ness of  sap  in  the  young  tissues,  whereby  the  new  cells  are  softened 
1  Translated  from  "Archiv  d.  Phar.,"  Dec,  1877,  by  L.  v.  Cotzhausen. 
