AmMi?ch,S%rn1"}    The  Apocynacece  in  Materia  Medica.  163 
brown  to  yellowish-brown,  fawn,  brick-red,. etc.,  the  tint  being  dull 
and  earthy.  The  perider,  mwhen  present,  is  very  tough  and  fre- 
quently bears  lichens. 
The  internal  face  is  finely  striated  lengthwise,  sometimes  the 
striae  are  sinuous.  The  color  of  this  face  varies  also  from  a  steel 
gray  to  a  much  darker  fawn  or  even  distinctly  rose. 
The  transverse  fracture  is  short,  strongly  granular  and  very  stony; 
with  a  lens  we  see  the  fascicles  of  fibres  come  to  the  surface  in  the 
internal  region.  The  vertical  fracture  shows  these  same  fibres  as 
small  white  lines.    The  taste  is  bitter  but  not  extremely  so. 
The  most  interesting  elements  in  the  anatomy  of  this  bark  are 
the  curious  fibres  which  it  bears  in  great  numbers,  but  always  iso- 
lated and  embedded  in  the  ordinary  parenchyma.  The  fibres  are 
large,  elongated,  spindle-shaped  ;  the  thickening  very  considerable 
in  concentric  zones  and  with  small  clear  lumen.  Each  fibre  is  sur- 
rounded completely  by  an  envelope  of  small  cells  forming  a  single 
layer,  in  which  each  cell  contains  a  large  rhombohedral  crystal  of 
calcium  oxalate. 
The  chemical  composition  is  extremely  complex.  The  first 
research  was  made  by  G.  Fraude,  who  extracted  an  alkaloid,  aspi- 
dospermine.  Hesse  demonstrated  the  presence  of  six  alkaloids  in 
this  bark :  Aspido spermine,  Aspidospermatine,  Aspidosamine,  Hypo- 
quebracine,  Quebrachine,  Quebrachamine,  and  a  neutral  body  Qne- 
brachol.  The  Aspidospermine  of  commerce  is  an  indefinite  mixture 
of  these  various  bodies.  Tanret  thinks  that  some  of  these  alkaloids 
are  produced  in  the  reactions  from  the  others.  He  has  extracted  like- 
wise two  new  sugars,  quebrachite  and  levogyre  inosite.  The  bark 
contains  also  tannin  and  starch.  According  to  Huchard  the  action 
of  Aspidospermine  appears  to  be  directed  especially  toward  the 
respiratory  centre.  It  augments  the  amplitude  and  then  the  fre- 
quency of  the  respiration,  diminishes  and  regulates  the  action  of 
the  heart  and  lowers  the  temperature.  Outside  of  this  action  due 
to  the  pure  Aspidospermine  all  the  alkaloids  are  antithermic,  but 
more  especially  Quebrachine ;  all  color  the  blood  a  vinous  or  cur- 
rant-red, all  cause  an  increase  in  salivary,  intestinal  and  renal  secre- 
tions; all  are  toxic,  especially  Quebrachine  and  Hypoqucbracine. 
The  least  toxic  is  Aspidospermine.    They  cause  death  by  asphyxia. 
Quebracho  is  employed  in  its  native  country  as  a  febrifuge,  and 
according  to  Schikendanz,  the  physicians  of  Tucuman  esteem  it  as 
