9°  North  American  Conifer  ce.  {^ebruaryTisw!10' 
A  CONTRIBUTION  TO  THE  KNOWLEDGE  OF  SOME 
NORTH  AMERICAN  CONIFERS. 
By  Edson  S.  Bastin  and  Henry  Trimbi/e. 
{Continued' from  Vol.  68,  page  648.) 
TSUGA  CANADENSIS. 
CHEMICAL  COMPOSITION. 
Considering  the  enormous  commercial  importance  of  this  tree 
and  its  products,  it  has  received  very  little  attention  by  the  botanist 
or  chemist.  No  investigations  have  been  reported  recently,  except 
two  on  the  volatile  oil,  so  that  the  text-books  at  the  present  time 
give  the  results  of  observations  made  from  twenty-five  to  fifty  years 
ago. 
The  Leaves. — The  most  important  constituent  of  the  leaves  is  the 
volatile  oil.  The  preparation  of  this  product  was  described  by 
Stearns1  in  a  report  to  the  American  Pharmaceutical  Association  in 
1858.  He  had,  from  a  practical  distiller,  the  information  that  in 
Michigan,  at  least,  the  oils  of  hemlock  and  spruce  (Picea  nigra)  were 
one  and  the  same  thing,  and  distilled  from  the  boughs  of  Tsuga 
Canadensis,  a  statement  which  is  probably  true  to-day. 
"  The  proceeding  is  as  follows  :  The  trees  are  cut  down  and 
the  boughs  collected  only ;  they  are  cut  up  fine  and  subjected  to  a 
distillation  with  water,  in  a  portable  copper  still  and  worm,  capable 
of  holding  about  one  hundred  gallons,  which  is  so  arranged  that  it 
can  be  transported  in  the  woods,  and  erected  quickly  upon  a  tem- 
porary arch ;  two  pails  full  of  boughs  (about  8  pounds)  are 
calculated  to  yield  1  ounce  of  oil.  The  distilling  is  done  only  in 
winter,  when  the  tree  is  richest  in  oil." 
Bertram  and  Walbaum,2  m  1894,  examined  oil  of  spruce,  said  to 
have  been  prepared  from  Abies  Canadensis  (Tsuga  Canadensis),  and 
found  it  to  consist  of  laevogyrate  pinene,  laevogyrate  bornyl  acetate 
(36  per  cent.)  and  a  sesquiterpene.  It  had  a  specific  gravity  of  0-907 
at  I5°C.  Carl  G.  Hunker3  considered  it  a  question  whether  this 
sample  was  derived  from  Tsuga  Canadensis,  or  from  Picea  nigra ;  he, 
therefore,  collected  the  leaves  and  twigs  of  Tsuga  Canadensis  him- 
self in  the  month  of  September,  and  submitted  them,  while  fresh,  to 
distillation  with  water  vapor.    The  yield  was  small,  of  a  yellowish 
1  Report  on  the  Medical  Plants  of  Michigan,  Am.  Jour.  Pharm.  1859,  P-  28* 
2Archiv  der  Pharm.,  231,  294. 
3  Pharmaceutical  Review,  14,  34. 
