736  Samples  of  ''Grey  Cinchona  Bark.  {^'^o{ZLl\"^9ro[ 
marked.  The  transverse  cracks  often  extend  nearly  round  the 
large  quills.  The  microscope  shows  a  thick  layer  of  cork  cells, 
isolated  sclerenchymatous  cells  in  the  cortical  parenchyma,  and  the 
liber  fibers  are  mostly  isolated  and  arranged  in  radial  lines. 
The  specimens  received  from  Mr.  B.  F.  Howard  consist  mainly 
of  pieces  of  bark  exhibiting  the  characters  attributed  to  C.  Peruvi- 
ana How.,  by  Planchon  and  Collin,  and  show  the  anatomical  struc- 
ture of  that  bark  as  illustrated  and  described  by  those  authors  and 
also  as  described  by  Vogl.  Some  of  the  pieces  differ  in  the  greater 
number  of  sand  cells  and  in  the  smaller  number  of  the  stone  cells 
in  the  cortical  parenchyma. 
The  larger  percenatge  of  cinchonine  found  in  this  shipment  of 
Huanuco  bark  may  possibly  be  due  to  the  elevation  at  which  the 
trees  grow,  as  this  factor  and  the  accompanying  differences  of  heat 
and  moisture  are  known  to  influence  the  character  of  the  alkaloids 
present.  In  the  present  state  of  our  knowledge  of  the  species  of 
the  Cinchona  genus  occurring  in  Peru  I  can  only  come  to  the  con- 
clusion that  the  bark  submitted  to  me  for  examination  is  the  produce 
of  one,  or  possibly  more,  forms  of  C.  Peruviana  How.,  as  inter- 
preted in  the  illustration  given  by  Planchon  and  Collin  and  Berg. 
The  authors  were  at  a  loss  to  understand  the  presence  of  Cin- 
chona officinalis  in  a  grey  bark,  and  they  also  considered  that  if 
this  variety  were  present  in  any  quantity  it  would  inevitably  affect 
the  alkaloidal  contents.  As  has  been  shown  above,  nitida,  Peru- 
viana, and  micrantha  have  always  appeared  to  yield  an  exceptionally 
large  amount  of  cinchonine,  and  this  peculiarity  has  never  been 
known  to  occur  in  the  much  less  rare  officinalis  bark. 
In  order  to  establish  the  presence  or  otherwise  of  ''officinalis" 
in  this  parcel,  a  fresh  sample  was  drawn  from  the  bulk,  and  again 
submitted  to  Mr.  Holmes  for  his  opinion.  In  this  fresh  sample 
he  could  find  no  C.  officinalis,  but  classified  it  into  three  varieties. 
nitida,  Peruviana,  micrantha,  together  with  another  variety  some- 
what resembling  Pitayensis,  and  which  might  either  belong  to  this 
or  the  Lucumaefolia  variety,  or  might  possibly  be  a  new  variety  alto- 
gether. From  this  examination  it  is  fair  to  assume  that  the  presence 
of  a  small  quantity  of  officinalis  in  the  first  sample  was  purely  acci- 
dental and  not  typical  of  the  parcel,  and  that  the  amount  was  so 
small  that  it  did  not  affect  the  unusual  distribution  of  alkaloids. 
The  analyses  of  the  varieties,  as  identified  by  Mr.  Holmes,  were 
as  follows: 
