9o 
Pharmaceutical  Notes. 
(Am.  Jour.  Pharm. 
\    February,  1895. 
From  the  fact  that  evolution  of  the  hydrogen  sulphide  gas  only 
took  place  in  the  syrup,  containing  free  acids,  the  writer  drew  the 
conclusion  that  it  must  be  due  to  another  cause. 
A  number  of  experiments  led  him  to  the  conclusion  that  the 
source  laid  in  the  ultramarine,  added,  as  already  stated,  for  the  pur- 
pose of  "whiting." 
To  understand  the  reaction,  by  which  the  evolution  of  the 
gas  is  produced,  the  composition  of  the  pigment  must  be  briefly 
noticed. 
The  exact  constituents  are  not  well  known,  but  ultramarine  is 
stated  to  be  mainly  a  mixture  of  aluminum  silicate,  containing 
traces  of  iron,  together  with  various  sodium  compounds,  predomi- 
nant among  which  is  the  sulphide.  When  free  acids  act  upon  the 
latter,  hydrogen  sulphide  is  evolved. 
If  this  takes  place  in  medicinal  syrups,  it  is  recognized  by  its 
odor  or  by  suspending  a  strip  of  white  paper  moistened  with  lead 
acetate  solution   in  the  air  space  above  the  syrup  in  its  container. 
Syrups  containing  mineral  acids  claim  our  first  attention.  Of 
these  the  most  important  official  ones  are  those  containing  free  phos- 
phoric or  hypophosphorous  acid,  also  the  syrup  of  hydriodic  acid. 
These  acids  will  decompose  the  blue  readily  in  the  manner  men- 
tioned. 
The  action  of  acids  upon  the  pigment  is  not  confined  to  inor- 
ganic acids,  but  the  organic  produce  a  like  effect. 
Among  the  latter  may  be  mentioned  citric,  acetic,  tartaric  and 
oxalic  acids. 
Syrup  of  the  former  acid,  official  in  the  Pharmacopoeia,  is  not 
rarely  affected,  as  well  as  the  hypophosphite  syrup  of  the  last  Phar- 
macopoeia, which  also  contained  this  acid. 
Syrups  containing  acetic  acid,  such  as  ipecac,  garlic,  and  squill, 
will  also  show  the  same  effect,  although  in  not  as  characteristic  a 
manner,  as,  for  instance,  in  the  case  of  garlic  syrup  one  odor  will 
mask  the  other. 
Among  other  official  syrups  likewise  subject  to  this  change,  syrup 
of  gum  arabic  may  be  mentioned. 
The  mucilage  of  acacia  has  an  acid  reaction,  and  its  mixture  with 
simple  syrups,  containing  ultramarine  in  suspension,  will  be  found 
to  acquire  an  offensive  odor  on  prolonged  standing. 
Incidentally  may  be  mentioned,  that  the  same  effect  is  noticeable  in 
