492  Notes  on  Estimating  Eucalyptol.  {A^ciober,Pi898rm' 
Starch  was  found  in  the  rhizome.  An  estimation  of  it  made  on 
the  fresh  material  showed  1*67  per  cent. 
A  special  examination  of  a  kilogramme  of  the  rhizome  for  sapo- 
nin was  made  by  the  method  of  Christophsohn  and  Otten,  but  the 
principle  was  not  found. 
NOTES  ON  ESTIMATING  EUCALYPTOL.1 
By  Layman  F.  Kebi,e;r. 
From  the  great  variety  of  oils  of  eucalyptus  met  with  in  com- 
merce, it  would  seem  that  each  species  (about  120)  of  the  Euca- 
lyptus genus,  yielded  a  distinctively  characteristic  oil.  Just  how  to 
differentiate  the  officially  recognized  oils  from  the  undesirable 
material  is  not  an  easy  task ;  especially  when  it  is  remembered 
that  the  U.S. P.  recognizes  the  oils  distilled  from  the  fresh  leaves  of 
Eucalyptus  globulus,  Labillardiere;  Eucalyptus  oleosa,  F.  v.  Muller, 
and  some  other  species  of  Eucalyptus, 
The  specific  gravity  is  a  valuable  indicator  when  the  oil  is 
"  straight,"  but  the  oils  can  be  so  mixed  as  to  render  this  factor  of 
little  service.  The  same  is  true  of  the  rotatory  power.  The  phellan- 
drene  test  is  of  considerable  service,  but  what  is  wanted,  after  all, 
is  the  amount  of  eucalyptol  in  the  oil. 
In  1894  Mr.  L.  R.  Scammell2  took  out  a  patent  for  the  prepara- 
tion of  eucalyptol  on  a  large  scale.  The  basis  of  this  patent  is  the 
property  of  eucalyptol  to  form  a  crystalline  compound  with  phos- 
phoric acid  of  a  certain  strength.  The  process  consists  in  adding 
concentrated  phosphoric  acid  (Sp.  Gr,  1.75  to  1.785,  preferably  the 
latter),  in  slight  excess,  to  the  oil  at  the  ordinary  temperature,  but 
not  above  6o°  F.  The  eucalyptol  phosphate  crystallizes  out,  is 
purified  by  pressure  or  centrifugally,  and  is  then  decomposed  with 
hot  water. 
Just  how  far  this  process  will  lend  itself  to  quantitatively  estimat- 
ing eucalyptol  is  fairly  well  settled.  Mr.  Faulding,  commenting3 
on  the  method,  lauds  it  to  the  skies,  but  does  not  give  any  data  for 
his  affirmations.    Mr.  Helbing,4  on  the  other  hand,  considers  the 
1  Read  at  the  Baltimore  meeting  of  the  American  Pharmaceutical  Association. 
2  1894,  Eng.  Pat.,  No.  14,138,  July  23d. 
3  1895,  Chemist  and  Druggist,  46,  310. 
1  Pharm.  Record,  No.  33,  p.  26. 
