580 
Correspondence. 
f  Am.  Jour.  Pharm. 
\    December,  1907. 
there  is  at  present  little  unanimity  among  chemists,  excepting  cam- 
phor. It  was  deemed  advisable,  however,  to  indicate  the  chief  steps 
involved  by  using  some  formulas.  Criticisms  were  expected. 
Bredt's  formula  for  camphor  and  pinene  were  intended  to  be  used. 
The  formula  for  camphor  as  it  appears  in  the  article  is  incorrect. 
The  error  was  noticed  in  the  proof  and  corrected,  but,  for  some 
reason,  the  printer  did  not  make  the  necessary  change.  The  adja- 
cent CO  and  CH2  groups  are  interchanged  and  should  be  transposed. 
It  is  true  that  a  number  of  investigations  have  been  made  since 
Bredt  suggested  his  structural  formula  for  pinene,  but  the  best  that 
can  be  said  for  same  is  that  the  formula  suggested  by  Wagner  (the 
one  claimed  by  Mr.  Tutin,  "  now  generally  accepted  ")  is  indicated. 
Concerning  this  formula,  F.  Heusler,  in  his  book  translated  by  F.  J. 
Pond,  entitled  "  Chemistry  of  the  Terpenes,"  page  47,  makes  the 
following  statement : 
"  In  the  critical  consideration  of  the  constitutional  formulas  of 
pinene,  and  other  members  of  the  terpene  series,  which  have  been 
advanced  by  G.  Wagner  during  the  course  of  his  investigations 
above  referred  to,  the  incompleteness  of  the  experimental  founda- 
tions for  these  formulas,  as  is  sufficiently  observed  from  what  has 
been  mentioned,  must  not  be  neglected." 
Relative  to  the  criticism  of  structural  formulas  for  camphor  and 
pinene,  appearing  upon  page  353,  it  is  only  necessary  to  state  that 
they  are  the  ones  used  in  the  patent,  and  represent  the  ideas  of  one 
investigator. 
Very  few  chemists  have  ventured  to  suggest  structural  formulas 
for  either  borneol  or  isoborneol.  Those  used  in  my  communication 
will  be  found  in  an  article  published  by  Dr.  W.  Gbssling  in  the 
Pharm azeutische  Post,  Volume  38,  page  599.  So  far  as  I  know  no 
criticism  has  appeared  in  subsequent  numbers  of  the  Pharmazeuti- 
sche  Post  or  other  literature  relative  to  these  formulas.  The  criti- 
cisms of  Mr.  Tutin,  excepting  the  correction  in  the  camphor  formula 
are,  in  my  opinion,  not  well  founded. 
Respectfully, 
L.  F.  Kebler. 
Washington,  D.  C,  December  2,  1907. 
