406 
Menthol. 
f  Am.  Jour.  Pharm. 
t     August,  1884. 
in  popular  favor,  until  now  it  may  be  found  in  a  variety  of  forms  in 
almost  every  drug  store. 
In  the  June  number  of  this  Journal  is  mentioned  a  menthol  from 
M.  piperita,  for  which  the  name  "Pipmenthol"  is  very  properly  sug- 
gested, to  indicate  its  origin,  and  distinguish  it  from  that  of  China. 
There  is  sufficient  physical  difference  between  the  two  to  warrant  the 
employment  of  different  names.  The  sample  furnished  me  by  Prof. 
Maisch  has  the  characteristic  odor  of  M.  piperita,  while  the  commer- 
cial menthol  has  a  peculiar  odor  resembling  a  mixture  of  peppermint 
with  other  members  of  the  mint  family.  The  crystals  are  "snow- 
Avhite  and  acicular,"  while  those  of  commercial  menthol  are  more  or 
less  transparent.  Chemically  the  two  are  undoubtedly  identical,  as 
the  following  experiments  will  show. 
Pipmenthol  fused  at  42°C;  several  determinations  confirmed  this. 
The  thermometer  used  was  compared  with  a  number  of  others  and 
found  to  be  accurate.  Japanese  menthol  fused  at  41°.  Three  com- 
bustions, one  of  pipmenthol  and  two  of  the  Japanese  were  made  with 
the  following  result  : 
Japanese. 
Calculated  foi-  Ci0H2oO,  Pipmenthol.  I.  II. 
C  76-92  77-14  79"63  79-33 
H  12-82  12-93  13*03  12-75 
O  10-26 
100-00 
The  difference  in  the  amount  of  carbon  in  the  Japanese  is  explained, 
as  is  the  lower  fusing  point,  by  the  presence  of  some  of  the  liquid  oil 
richer  in  carbon.  This  will  also  explain  the  low  fusing  point  given 
by  the  early  investigators. 
As  found  by  Beckett  and  Wright,  menthol,  after  exposure  to  air  for 
some  weeks  will  have  a  higher  fusing  point,  and  we  may  suppose  a 
lower  carbon  percentage.  The  pipmenthol  as  now  made  may  properly 
be  taken  as  a  standard  for  the  determination  of  the  properties  of  this 
substance,  and  there  is  little  doubt  but  that  the  Japanese  article  may 
be  so  purified  as  to  resemble  it  in  everything  but  odor. 
Philadelphia,  July  15,  1884. 
