AjuJn°eDl;]P8H72EM  }  Crystalline  Principle  of  Barbadoes  Aloes.  255 
of  the  characteristics  of  the  former,  we  may  regard  the  two  acids  as 
closely  related.  The  proper  name  of  this  constituent  would  be  jug- 
landic  acid. 
Solution  of  sulphate  and  tincture  chloride  of  iron  produced  dense  dark 
colored  precipitates,  but  other  tests  did  not  prove  the  presence  of 
tannin. 
The  decoction  affords  precipitates,  and  hence  is  incompatible  with 
the  sesqui-  and  proto-salts  of  iron,  bichromate  of  potassium,  sulphate  of 
copper,  acetate  of  lead,  and  nitrate  of  silver.  No  effect  is  produced  by 
yellow  and  red  prussiates  of  potassium,  tannin  and  antimonial  salts. 
The  bark  contains  bitter  extractive,  a  large  amount  of  oily  matter, 
juglandic  acid  (which  appears  to  be  related  to  chrysophanic  acid),  an 
acid  crystallizing  in  tabular  colorless  crystals,  a  volatile  acid,  and  no 
tannin.  The  ashes  were  found  to  contain  a  considerable  percentage 
of  potassium,  with  traces  of  sodium,  calcium  and  aluminium. 
NOTE  ON  CRYSTALLINE  PRINCIPLE  OF  BARBADOES  ALOES.* 
By  William  A.  Tilden,  D.Sc.  London, 
Demonstrator  of  Practical  Chemistry  to  Pharmaceutical  Society,  G.B. 
This  substance  was  examined  some  years  ago  by  Dr.  Stenhouse, 
who  analyzed  it  and  a  bromo-derivative. 
After  several  unsuccessful  trials,  I  have  obtained  from  it  a  ehloro- 
substitute,  corresponding  to  the  brominated  body  already  known.  It 
is  only  necessary  to  treat  the  aloin  with  excess  of  chlorine  in  the 
presence  of  concentrated  hydrochloric  acid.  This  is  most  conveniently 
done  by  the  method  adopted  by  Stenhouse  in  preparing  the  chlori- 
nated derivatives  of  orcin. 
Some  powdered  potassic  chlorate  was  introduced  into  a  quantity  of 
ordinary  fuming  hydrochloric  acid.  The  crystallized  aloin  to  be  oper- 
ated upon  was  dissolved  in  another  portion  of  the  same  acid,  and  the 
solution  so  obtained,  when  quite  cold,  was  poured  gradually  and  with 
constant  agitation  into  the  mixture  of  hydrochloric  acid  and  chlorate. 
After  each  addition  of  the  aloTn,  a  red  coloration  was  produced,  but 
this  instantly  disappeared,  the  solution  assuming  a  clear  orange  color, 
and  depositing  in  a  few  minutes  a  copious  crop  of  yellow  granules, 
V  the  quantities  of  which  increased  by  standing  for  a  few  hours.  It 
was  then  filtered  oft",  washed  with  a  little  water,  and  crystallized  from 
*  Reprint  from  the  Journal  of  the  Chemical  Society,  March,  1872.  Com- 
municated by  the  author. 
