556 
Unguentum  Zinci  Oxidi. 
f  Am.  Jour.  Pharm. 
1      Nov.,  1881. 
more  or  less  compressed  towards  the  w^ood^  which  is  traversed  by  many 
medullary  rays  and  contains,  chiefly  in  the  outer  portion,  a  number  of 
vessels.  The  bark  is  composed  of  oblong  cells,  diflPering  in  size  and 
containing  starch  ;  a  few  laticiferous  vessels  are  seen  and  several  groups 
of  thick-walled  bast  cells,  arranged  somewhat  in  a  circle  near  the 
middle  of  the  bark. 
The  root  of  Apoc.  cannabinum  shows,  in  the  transverse  section,  in 
the  centre  a  few  small  round  cells.  Then  follows  the  wood,  showing 
about  three  annual  layers,  vessels  somewhat  arranged  in  rows,  and 
many  medullary  rays  running  into  the  bark.  The  cells  of  the  bark 
are  roundish,  contain  an  abundance  of  starch  and  also  numerous  lati- 
ciferous vessels. 
The  author  also  examined  microscopically  the  root  that  had  been 
sold  to  hiui  as  tliat  of  Ap.  andros^emifolium,  and  found  it  in  most 
respects  to  agree  physically  and  microscopically  with  the  root  of  Apoc. 
cannabinum  examined  by  him,  the  differences  observed  (two  circles  of 
wood,  curved  medullary  rays,  etc.)  being  of  no  importance.  It  is 
quite  likely  that  nearly  all  the  fluid  extract  of  Apoc.  androsaemifolium 
which  is  sold  in  our  market  has  been  made  of  this  substitute  or  of 
Apocynum  cannabinum. 
Unguentum  Zinci  Oxidi. — 
Editor  American  Journal  of  Pharmacy : 
Dear  Sir — Having  tried  several  formulas  for  preparing  oxide  of 
zinc  ointment,  I  have  settled  upon  the  following  as  easy  of  prepara- 
tion and  without  use  of  other  ingredients  than  those  of  the  Pharma- 
copoeia. It  was  suggested  by  the  use  of  glycerin  in  the  process  of 
Mr.  E,.  F.  Fairthorne;  I  also  use  white  wax,  it  being  impossible  to 
keep  the  ointment  of  proper  consistency  in  this  climate  without  such 
addition;  I  strain  benzoated  lard,  as  recommended  by  Mr.  H.  M. 
Wilder,  it  giving  a  nicer  preparation  and  keeping  equally  as  well  as 
the  unstrained.  Rub  the  oxide  of  zinc  to  a  fine  powder,  place  in  a 
warm  uiortar  and  gradually  add  the  lard,  previously  melted,  tritur- 
ating thoroughly;  stir  until  cool;  if  wax  is  added  it  should  be  melted 
with  the  benzoated  lard.  While  I  do  not  claim  the  process  to  be 
original,  it  is  at  least  so  with  myself.  I  send  it,  thinking  it  may  be 
of  use  to  your  other  numerous  readers  who  have  been  annoyed  with 
the  ointment.    The  ointment  is  smooth  and  white  and  does  not  spoil. 
Yours  truly,  R.  Anton. 
Savannah,  Ga.,  Sept.  13,  1881. 
