m.  Jour.  Pharm.  \ 
August,  1896.  J 
North  American  Conifer ce. 
421 
is  purified  by  melting  and  straining  through  straw.  When  heated 
sufficiently  long  it  is  deprived  of  all  of  its  volatile  oil  and  water, 
and  becomes  clear  and  of  a  brown  color.  The  composition  of  the 
resin  has  not  been  studied,  but  it  is  said  to  consist  largely  of 
abietic  acid,  and  thereby  closely  resembles  the  resin  of  turpentine. 
ECONOMICS. 
The  wood  of  this  species  is  elastic,  light,  not  very  strong,  and 
varies  in  its  durability  according  to  the  soil  in  which  it  grows.  The 
Pk 
Fig-  15- — Cross-section  of  leaf  of  Picea  excelsa,  magnified  75  diameters. 
Ep,  epidermis  ;  hy,  hypoderma  ;  m,  mesophyll ;  st,  stoma  ;  en,  endodermis  ;  t, 
transfusion  tissue  ;  xy,  xylem  of  bundle  ;  ph,  phloem  of  bundle.  This  section 
does  not  happen  to  show  the  secretion  reservoirs  often  found  at  the  lateral 
angles  of  the  leaf. 
bark  is  employed  for  tanning.  The  buds  and  young  shoots  are 
employed,  like  those  of  P.  nigra,  for  the  purpose  of  brewing  a  beer. 
The  wood  is  also  extensively  used  in  construction,  for  ladders,  spars, 
oars,  the  masts  "of  vessels,  and  for  sawing  into  lumber  which  is  used 
for  a  great  variety  of  purposes. 
The  wood  is  fine-grained  and  takes  a  high  polish,  and  hence  is 
much  employed  in  the  cabinetmaker's  art  and  in  the  constructicn 
of  musical  instruments. 
