212 
Rhus  Ai'omatica. 
/  Am.  Jour.  Pharro. 
i     May,  1881. 
laiy  rays  extend  more  than  half  through  the  bark  and  consist  mostly 
of  a  single  row  of  cells.  The  oil  tubes  are  generally  in  the  bast  rows, 
arranged  with  some  regularity.  In  some  of  the  sections  examined 
three  or  four  of  the  oil  tubes  were  found  coalesced,  as  in  Fig.  I. 
The  bark  is  studded  with  crystals,  which  seem  to  be  mostly  confined 
to  the  portion  beyond  the  medullary  rays.  The  crystals  were  exam- 
ined under  a  high  magnifying  power,  which  showed  them  as  repre- 
sented in  Figs.  Ill,  IV  and  V,  the  latter  predominating,  only  a  few 
of  Figs.  Ill  and  IV  being  clearly  made  out. 
Fig.  II.  A  longitudinal  section  of  the  bark,  in  a  radial .  direction 
(magnified  the  same  as  Fig.  I),  showing  the  longitudinal  arrangement 
of  the  tissues,  oil  tubes  and  crystals,  sections  of  two  medullary  rays 
being  quite  prominent. 
Fig.  Ill  represents  crystals  of  the  phosphates,  Fig.  IV  crystals  of 
the  chlorides,  and  Fig.  V  crystals  of  oxalate  of  calcium  as  they 
appeared  under  a  high  magnifying  power. 
Chemical  Investigation. — Five  grams  of  the  air-dry  bark  subjected 
to  a  heat  of  100°C.  until  it  ceased  to  lose  weight  weighed  4*651 
grams,  showing  a  loss  of  '349  gram  =  6 "98  per  cent,  amount  of 
moisture. 
Five  grams  of  the  air-dry  h^xk  were  incinerated,  and  yielded  '644 
gram  of  ash,  equal  to  13*85  per  cent.,  of  which  16*967  per  cent,  was 
soluble  in  water,  74*007  per  cent,  soluble  in  hydrochloric  acid,  and 
9*025  per  cent,  soluble  in  boiling  sodic  hydrate.  An  analysis  showed 
the  presence  of  potassium,  sodium,  aluminium,  calcium  and  silica, 
combined  as  sulphates,  chlorides  and  phosphates  in  the  aqueous  solu- 
tion, and  as  phosphates  and  carbonates  in  the  portion  soluble  in  hydro- 
chloric acid ;  the  carbonates  very  likely  were  produced  during  the 
incineration. 
Twenty  grams  of  the  powdered  bark  were  exhausted  with  pure 
benzol  by  maceration  and  percolation ;  the  percolate  was  allowed  to 
evaporate  spontaneously,  yielding  an  extract  weighing  1*272  gram  = 
6*36  per  cent.  This  extract  was  treated  with  warm  water,  allowed  to 
cool,  filtered,  and  filtrate  tested  for  alkaloids  and  glucosides  with  nega- 
tive results.  The  undissolved  extract  was  removed  from  the  filters  and 
dishes  by  solution  in  benzol,  the  benzol  solution  again  evaporated  to 
dryness,  the  residue  treated  with  warm  dilute  sulphuric  acid,  allowed 
to  cool  and  then  filtered.  The  filtrate  was  tested  for  alkaloids  and 
glucosides ;  negative  results.    The  still  undissolved  residue  was  thor- 
