194 
Pipitzahoic  Acid  or  Vegetable  Gold. 
J  Am.  Jour.  Pharni. 
\      April,  1884. 
pipitzahoic  acid  is  contained  in  secreting  cells,  in  groups  of  from  three 
to  five;  the  acid  is  in  yellow  lumps  of  a  crystalline  structure.  These 
depositories  of  the  acid,  striking  in  the  entire  section,  are  arranged  in 
a  circle  and  correspond  to  the  fibrovascular  bundles.  Stellate  spots 
are  scattered  throughout  the  fundamental  tissue  from  the  collenchyma 
to  the  centre  of  the  root  and  are  due  to  certain  cells  only  of  the 
tissue  becoming  thickened  by  secondary  deposit,  and  converted  into 
sclerenchymatous  or  stone  cells  with  laminated  structure,  the  intercel- 
lular spaces  being  filled  with  a  dark  colored  deposit.  These  cells  are 
found  mostly  single,  but  occasionally  in  groups  of  two,  three  or  more. 
A  longitudinal  section  shows,  in  addition  to  the  relative  positions  of 
the  cells  referred  to,  the  more  characteristic  constituents  of  the  root  as 
pipitzahoic  acid,  and  the  dark  deposit  around  the  long  stone  cell  tra- 
versing the  length  of  the  root. 
Most  of  the  parenchymatous  cells  contain  grains  of  inulin,  Perez ia 
being  one  of  the  Composite,  and  containing  inulin  as  the  equivalent 
of  starch  present  in  the  plants  of  other  orders. 
This  brief  account  of  the  microscopical  structure  of  the  Perezia  root 
will  serve  to  make  the  more  salient  features  in  its  histology  intelligible. 
The  quantity  of  root  placed  at  my  disposal  was  only  2  gm.,  and  that 
of  acid  0*33  gm.;  it  must,  therefore,  be  obvious  that  few  experiments 
beyond  those  afforded  by  micro-chemistry  could  be  undertaken. 
A  transverse  section  of  the  root  in  which  the  lumps  of  pipitzahoic 
acid  were  visible  were  subjected  to  micro-sublimation  on  a  microscopic 
glass  slide,  and  at  a  little  over  100°C.  the  acid  sublimed  on  the  cover- 
glass  in  yellow  crystals.  An  alcoholic  tincture  of  the  root,  yellow 
from  solution  of  the  acid,  brought  into  contact  with  a  dilute  solution 
of  caustic  alkali  or  alkaline  carbonate,  developed  that  fine  purple  color 
which  induced  Herr  Yigener  to  suggest  a  probable  future  for  the  acid 
as  a  color  indicator  in  chemical  investigations.  The  tincture  on  evapo- 
ration yielded  crystals  of  pipitzahoic  acid. 
I  was  unable  to  satisfy  myself  as  to  the  character  of  the  intercellular 
dark  deposit.  It  Avas  not  affected  by  alcohol,  ether,  benzol,  chloroform 
or  turpentine;  neither  did  caustic  alkali  dissolve  it;  it  was  decomposed 
by  nitric  acid.  If  from  the  negative  results  of  these  experiments  I 
may  be  allowed  to  offer  an  opinion,  it  would  be  that  the  deposit  in 
question  is  dried,  latex.  ; 
When  the  pipitzahoic  acid  first  came  under  my  notice  it  occurred  to 
me  as  probable  that  its  formation  might  be  due  to  a  degradation  of 
