oSobeTi9?o"'"  l    Samples  of  ''Grey  Cinchona  Bark.  731 
tween  colorless  lard  and  the  yellow  milk  fat  and  egg  fat.  Hence 
Steenbock^  has  advanced  the  theory  that  the  vitamin  may  be 
yellow  pigment  or  at  any  rate  a  closely  associated  substance.  His 
latest  contribution  is  corroboratory;  it  also  indicates  that  the  vita- 
min attends  the  carotin  rather  than  the  xanthophyll  variety  of  pig- 
ments, either  or  both  of  which  may  represent  the  yellow  coloring 
matter  in  animal  and  plant  foods.  These  findings,  if  they  are  further 
substantiated,  mark  a  distinct  step  in  advance  toward  the  goal  of  dis- 
covering the  nature  of  the  fat-soluble  vitamin. 
SOME  RECENT  SAMPLES  OF  "GREY"  CINCHONA  BARK.* 
By  Bernard  F.  Howard,  F.I.C,  and  Oliver  Chick,  A.I.C. 
Grey  Bark  of  Huanuco  (a  locality  of  Lower  Peru)  was  a  fairly 
common  kind  of  Peruvian  bark  to  be  met  with  on  the  London  mar- 
ket in  the  sixties  and  seventies,  but,  owing  to  its  low  quinine  content 
and  the  severe  competition  of  rich  Java  barks,  its  importation  grad- 
ually diminished,  and  for  the  last  twenty  years,  at  any  rate,  it  has 
been  almost  unknown  as  a  bark  of  commerce. 
The  temporary  shortage  of  cinchona  due  to  the  war,  howeve^r, 
has  caused  it  to  reappear,  and  the  authors  have  had  the  oppor- 
tunity of  studying  several  samples  of  good-sized  parcels  from  the 
point  of  view  of  modem  analytical  methods. 
The  literature  of  Grey  Bark  dates  almost  entirely  from  the 
period  mentioned  above,  botanically.  Weddell,  in  his  "Notes  on 
the  Quinquinas,"  published  in  1871,  p.  39,  states  that  Cinchona  nitida 
together  with  C.  Peruviana  and  C.  micrantha,  supplies  the  market 
with  "Quinquina  gris,"  or  grey  bark,  and  it  seems  generally  agreed 
among  all  experts  that  a  normal  sample  of  grey  bark  would  be 
expected  to  contain  these  three  varieties. 
From  the  analytical  point  of  view,  most  of  the  published  work, 
dating  back  some  fifty  years  or  more,  is  necessarily  vague,  owing 
probably  to  the  fact  that  the  methods  of  separation  and  estima- 
tion of  the  various  alkaloids  in  the  bark  were  at  that  time  very  un- 
certain. J.  E.  Howard  stated  (Pereia,  "Mat.  Med.,"  Vol.  H,  Pt. 
n,  p.  98,  fourth  edition)  that  he  found  "nearly  twice  as  much 
^  Steenbock,  H.:  "White  Corn  vs.  Yellow  Com  and  a  Probable  Relation  be- 
tween the  Fat-Soluble  Vitamine  and  Yellow  Plant  Pigments,"  ^a'ewc^,  50:  352 
(Oct.   10),  1919. 
*Reprinted  from  The  Pharmaceutical  Journal  and  Pharmacist,  July  24,  1920. 
