AFebr°uUarrVP?8a97m'}         North  American  Conifer  ce.  97 
This  is  a  considerable  variation  from  our  figures  given  for  hemlock 
tannin  and,  in  fact,  from  those  of  a  larger  number  of  other  tannins, 
and  it  appears  reasonable  to  attribute  this  difference  to  the  fact  that 
Boettinger  operated  on  a  commercial  extract  of  hemlock.  To  those 
familiar  with  the  manufacture  of  tanning  extracts  this  would  be  a 
sufficient  reason  for  allowing  his  results  to  await  further  research  on 
the  bark.  Much  assistance  on  the  chemical  investigation  of  this 
tannin  was  given  by  J.  C.  Peacock  and  W.  E.  Ridenour,  who  also 
aided  in  the  collection  of  the  various  samples  used  in  the  estimations. 
ECONOMICS. 
When  Ellis  wrote  concerning  this  tree  in  1830,  the  wood 
was  considered  of  very  little  value,  but  the  steady  diminution 
of  our  forests  has  brought  this  wood  to  the  front,  and  it  is  now  one 
of  the  most  important  lumber  trees  in  northeastern  United  States. 
The  hemlock  trunks  also  found  use  before  iron  became  so  cheap,  in 
conveying  water.  A  case  was  reported  in  18621,  where  pipes  of  this 
wood  had  been  in  service  thirty-two  years,  and  where  the  earth  was 
moist  they  had  not  decayed.  The  resin  has  had  extensive  use  in 
the  manufacture  of  plasters,  and  is  still  employed  for  that  purpose. 
The  volatile  oil  from  the  branches  is  used  as  a  flavoring  and  for  dis- 
infecting purposes.  The  bark  is  used  to  an  enormous  extent  in  the 
manufacture  of  heavy  leather.  In  recent  years,  many  tanneries  have 
been  built  in  the  hemlock  districts,  so  as  to  be  near  the  supply  of 
bark.  For  the  finer  grades  of  leather  the  hemlock  bark  is  mixed 
with  that  of  the  oak,  in  order  to  avoid  the  reddish  color  produced 
by  the  former. 
An  extract  of  the  bark  is  employed  by  tanners  in  place  of  the 
bark,  or  to  strengthen  their  bark  liquors,  and  in  a  variety  of 
other  ways,  notably  by  dyers,  in  conjunction  with  logwood  coloring, 
to  modify  the  shades  of  the  latter,  especially  when  copper  sulphate 
is  used  as  the  mordant.  Large  quantities  of  hemlock  extract  go  to 
the  European  markets,  where  it  finds  ready  sale.  All  parts  of  the 
tree  are  used  except  the  root,  and  from  what  we  have  seen  of  its 
contents  of  tannin  we  may  look  forward  to  the  day  when  it,  too, 
will  not  be  allowed  to  go  to  waste. 
( To  be  contin ued. ) 
1  Am.  Jour.  Pharm.,  34,  377. 
