372  Preparation  of  Salvarsan.  {"^'aiS' rJiT™' 
soluble  in  alkaline  solutions,  they  are  exceedingly  paniful  when 
injected;  hence  the  need  for  a  neutral  suspension  of  the  base  itself. 
The  material  having  been  prepared,  as  previously  directed,  the 
ampoule  containing  the  drug  is  washed  with  w^ater  and,  finally,  with 
alcohol.  This  is  necessary  because  they  are  generally  badly  smeared 
with  glue.  The  ampoule  is  then  opened  and  emptied  immediately 
into  the  mortar.  Fifteen  or  sixteen  drops  of  the  soda  solution  are 
added  and  mixed  with  the  material.  Then  enough  distilled  water  is 
added,  drop  by  drop,  to  make  a  moderately  thin  paste.  Great  care 
must  be  taken,  from  this  point  to  the  end  of  the  preparation,  to 
thoroughly  triturate  the  material.  Every  particle  must  be  rubbed 
till  a  smooth,  creamy  mixture  results.  It  is  now  to  be  tested  for 
alkalinity  by  applying  a  small  portion  of  the  mixture,  by  means  of  one 
of  the  rods,  to  a  piece  of  phenolphthalein  paper.  If  not  faintly  alka- 
line add  soda  solution,  drop  by  drop,  with  continued  trituration,  till 
it  gives  the  reaction,  adding  sterile  water,  from  time  to  time,  if  the 
preparation  becomes  too  thick.  Now  the  HCl  solution  is  added,  drop 
by  drop,  till  the  mixture  just  ceases  to  react  upon  the  test  paper. 
Great  care  must  be  taken  to  rub  up  any  cheesy  lumps  that  may  form 
when  the  acid  is  added.  More  water  is  added  and  the  mixture 
transferred  to  the  graduated  cylinder.  The  portions  of  the  precipi- 
tate adhering  to  the  sides  of  the  mortar  and  the  pestle  are  rinsed 
down  with  the  aid  of  a  glass  rod  and  sterile  water,  dropped  as 
needed,  and  added  to  that  in  the  cylinder.  Enough  water  is  added 
to  make  the  product  measure  8  c.c.  and  the  mixture  transferred  to 
the  ampoule  by  means  of  the  funnel.  Two  c.c.  of  water  are  now 
used  to  rinse  the  adhering  material  from  the  measure  and  funnel 
into  the  ampoule.  The  excess  of  stem  is  filed  and  broken  from 
the  ampoule,  which  is  immediately  sealed  by  a  blow-pipe  flame 
directed  across  the  edge  of  the  open  tube  till  the  glass  is  perfectly 
fused.    After  cooling,  the  container  is  shaken  to  insure  mixing. 
Many  physicians  make  the  injection  at  two  sites,  using  the 
suspension  in  portions  of  5  c.c  each.  For  this  purpose,  a  beaker 
glass  will  be  needed  in  dividing  the  preparation.  An  extra  beaker 
is  provided  because  the  operator  frequently  has  immediate  need  of 
an  extra  vessel  of  some  kind  in  the  midst  of  his  work. 
It  is  better  to  have  a  large  mortar  than  one  too  small,  as  the 
precipitate  can  be  more  easily  rubbed  smooth  in  the  former.  A 
porcelain  dish  as  directed  in  the  circulars  is  exceedingly  unsatis- 
factory. 
