Am.  Jour.  Pharm.  I 
Dec,  1883.  J 
The  Trees  Yielding  Benzoin. 
619 
acids.  The  purest  form  of  algin  is  tiie  precipitate  produced  by  a 
mineral  acid.    It  dries  to  a  hard  horny  substance. 
The  composition  of  this  substance  is  still  obscure,  for  although  the- 
compounds  with  calcium,  aluminium,  barium,  and  lead  have  been 
investigated,  no  uniform  results  have  been  obtained.  The  sodium 
carbonate  appears  to  be  unaltered  in  its  compound  with  algin;  the 
carbonic  acid  is,  however,  only  given  off  by  treating  with  excess  of 
hydrochloric  acid,  and  heating.  When  a  solution  of  algin  is  precipi- 
tated by  acid,  redissolved  in  alkali,  and  this  treatment  repeated,  decom- 
position seems  to  go  on  continually.  The  author  then  suggests  various 
uses  for  algin,  founded  on  the  properties  above  described;  mixed  with 
starch  it  could  be  used  as  a  stiffener  for  fabrics,  or  alone  as  a  dressing 
material,  or  as  a  mordant.  It  would  also  form  a  useful  food.  It  can 
be  used  to  prevent  boiler  incrustations,  for  fining  wines  and  spirits,  for 
insulating  electrical  appliances,  etc.  It  can  also  be  used  to  replace 
horn  for  the  manufacture  of  various  moulded  articles. — Jour.  Chern.. 
Soc,  1883,  p.  943;  Chem.  Nem,  xlvii,  p.  254  and  267. 
THE  TREES  YIELDING  BENZOIN. 
By  E.  M.  Holmes,  F.L.S. 
The  benzoin  which  enters  into  English  commerce  includes  four 
varieties  named  respectively  Sumatra,  Palembang,  Penang  and  Siam 
benzoin.  These  exhibit  certain  characteristic  appearances  by  which 
they  are  easily  recognized,  and  three  of  them,  namely,  Sumatra, 
Penang  and  Siam  benzoin,  are  probably  derived  from  three  distinct 
plants.  The  botanical  source  of  Sumatra  benzoin  was  determined  by 
Dryander,  and  an  account  and  figure  of  the  Plant  were  published  by 
him  in  the  Philosophical  Transactions,  for  the  year  1787,  Ixxvii.,  p. 
303,  but  the  trees  which  yield  the  other  varieties  have  as  yet  never 
been  identified  with  certainty.  The  Penang  benzoin  is  similar  in 
appearance  to  the  Sumatra  kind,  but  it  has  an  oclor  which  is  quite 
distinct  and  resembles  that  of  storax.  It  is  in  all  probability  not  pro- 
duced by  Styrax  benzoin  ;  but  we  have  as  yet  no  accurate  information 
concerning  the  botanical  source  of  Penang  benzoin.  The  authors  of 
"  Pharmacographia  ^'  point  out  that  it  may  perhaps  be  the  produce  of 
Styrax  subdenticulata,  Miq.,  since  this  tree,  which  occurs  in  West 
Sumatra,  has  the  same  name,  "  Kajoe  Keminjan,"  as  S.  benzoin,  and 
