Am.  Jour.  Pharm. 
Feb.,  1884. 
Oleum  Betulce  Lentce. 
87 
it  was  rectified,  or  just  as  it  came  from  the  still ;  it  was  in  two  layers, 
and  decidedly  dirty,  the  layers  occupying  about  an  equal  space  in  the 
bottle.  After  freeing  it  from  dirt,  by  straining  through  flannel,  the 
layers  were  separated,  and  upon  examination  the  light  upper  layer  was 
found  to  be  nothing  but  water  impregnated  with  oil.  Its  specific 
gravity  at  70°F.  is  1*001.  The  lower  layer  proved  to  be  the  oil,  the 
specific  gravity  of  which  was  taken,  and  found  to  be  the  same  as  that 
examined  last  year,  1*181  at  70°F.,  thus  indicating  that  it  was  princi- 
pally methyl  salicylate.  This  oil  was  next  submitted  to  a  chemical 
analysis  in  the  same  manner  as  described  by  Mr.  Pettigrew :  50  grams 
of  the  oil  were  decomposed  with  25  grams  of  potassium  hydrate,  by 
boiling  for  six  hours  upon  a  sand-bath  ;  at  the  expiration  of  this  time 
the  oil  was  perfectly  decomposed,  and,  upon  cooling,  crystals  of  sali- 
cylate of  potassium  were  obtained,  and  a  clear  distillate,  without  oily 
layer,  nor  was  such  produced  upon  dilution  with  water.  This  obser- 
vation manifested  conclusively  the  absence  of  a  hydrocarbon.  To  get 
at  the  percentage  of  salicylic  acid  and  methyl  alcohol  was  the  next  step 
taken.  The  salicylate  of  potassium,  formed  as  indicated  above,  was 
decomposed  by  hydrochloric  acid,  which  liberated  the  salicylic  acid  in 
small  whitish  crystals,  requiring  only  to  be  drained  and  subsequently 
recrystallized  from  ether.  The  amount  obtained  from  50  grams  of  the 
oil  was  40  grams,  or  about  80  per  cent.  Another  bottle,  presented 
herewith  and  marked  "  impure/7  contains  the  acid  as  it  is  set  free  from 
the  potassium  salt.  This  was  obtained  from  an  old  oil,  made  last  year, 
and  has  not  been  recrystallized. 
I  then  proceeded  to  obtain  the  methyl  alcohol  from  the  oil  decom- 
posed as  described ;  the  liquid  portion  was  distilled  from  a  sand-bath, 
until  one-fourth  the  entire  amount  had  passed  over ;  this  was  redis- 
tilled, obtaining  one-fourth  as  before,  and  this  product,  to  get  rid  of 
the  water,  was  distilled  twice  from  lime.  The  methyl  alcohol  thus 
obtained,  which  is  also  shown,  approximates  8 J  grams,  or  17  per  cent. 
This  added  to  the  acid  yield  would  still  leave  a  discrepancy  of  3  per 
cent,  to  be  accounted  for. 
The  rectification  (as  it  is  termed)  of  the  oil,  to  which  I  referred  a 
year  ago,  is  accomplished  by  simply  straining  or  filtering  through 
cotton  and  flannel. 
The  yield,  as  I  have  already  stated,  from  the  distillation  made  Dec. 
26,  1884,  was  small;  it  required  7J  hours'  time  to  make  the  pound 
obtained.  In  the  spring,  when  the  sap  is  in  the  trees,  the  yield  is  from 
