346  Structure  of  Dye-Woods.  {^"^'^X^lz::^ 
of  every  hundred  grains  of  the  resin.  Every  five  grains  of  guaiac 
resin  contains  four  grains  of  guaiaconic  and  guaiaretic  acids  ;  then  five 
hundred  and  twelve  grains  will  be  the  amount  of  the  two  acids  present. 
Now,  986  :  112  :  :  512  :  58,  or  nearly  four  times  the  amount  called 
for  in  the  formula.  Acting  on  the  accuracy  of  this  calculation,  we 
made  syrupus  guaiaci,  using  58  grains  of  KHO  instead  of  the  one-half 
fluidounce  of  liquor  potassae  called  for,  and  the  result  was  a  small 
amount  of  residue,  a  much  darker  syrup  and,  therapeutically  and 
pharmaceutically,  a  better  preparation.  Allow  me,  then,  in  conclusionj, 
to  suggest  the  following  formula  for  syrup  of  guaiac  : 
R    Pulveris  guaiaci  resinas,  .  .  .  ^xxxii 
Potassic  hydrate,  ....  Iviii  grs. 
Sacchari  albi  .  .  .  .  Ibi  (avoird.) 
Aquae,  .  .  .  .  .  q.  s. 
Dissolve  the  KHO  in  8  fluidounces  of  water;  moisten  the  guaiac 
with  this  solution  ;  pack  it  in  a  percolator  and  gradually  pour  on  the 
balance  of  the  solution  ;  when  this  ceases  dropping  add  sufficient  water 
to  make  the  percolate  measure  eight  fluidounces  ;  add  the  sugar  and 
dissolve. 
A  STUDY  OF  THE  STRUCTURE  OF  DYE-WOODS.. 
By  Dr.  F.  R.  von  Hohnel, 
Lecturer  in  the  Polytechnic  Institute  of  Vienna. 
Translated  from  "  Dingler's  Polytech.  Jour.,"  by  Prof,  Sam'l  P.  Sadtler. 
Having  for  some  time  been  engaged  upon  a  thorough  histological 
and  histo-chemical  investigation  of  dye-woods,  I  recognized  the  neces- 
sity  of  establishing,  aided  by  accurate  macroscopic  examination,  some 
reliable  means  of  distinguishing  the  various  dye-woods  from  each  other 
and  from  woods  similar  to  them.  The  researches  of  Wiesner^  and 
Vogel^  afford  all  that  can  be  desired  as  regards  the  completeness  of  our 
knowledge  of  these  woods.  It  appeared,  however,  that  one  important 
point  remained  untouched,  viz.,  reliable  macroscopic  recognition.  The 
examination  of  dye-woods  with  the  naked  eye,  or  aided  by  the  lens,  as 
well  as  sufficient  consideration  of  differential  characters,  appear  to  have 
passed  unnoticed. 
^  Wiesner :  "Die  RohstofFe  des  Pflanzenreiches,"  p.  552. 
Vogel:  "  Untersuchungen  ueber  den  Bau,"  etc.,  in  "Lotos,"  March,  1873. 
