AjunTiR;iP872RM'}       Iodide  and  Bromide  of  Potassium.  247 
ly.   Morph.  Sulph.,  gr.  iv. 
Aquae  Cinnam.,  ^ij. 
Potass.  Bromid.,  Siij. 
Syr.  Tolut.,  3iss. 
Elix.  Calisayse,  3'iv.  M. 
The  morph.  sulph.  was  weighed  and  introduced  into  a  four-ounce 
vial,  the  potass,  bromid.  weighed  and  rubbed  in  a  mortar  with  the 
aqua  cinnam.  until  entirely  dissolved,  and  the  solution  poured  over 
the  morph.  sulph.  contained  in  the  vial.  The  morph.  sulph.  refusing 
to  dissolve  after  shaking,  the  vial  was  set  aside  and  the  preparation 
begun  anew. 
This  time  the  morph.  sulph.  was  dissolved  in  the  elix.  calisayae,  the 
potass,  bromid.  in  the  aqua  cinnam.,  and  the  two  solutions  mixed. 
A  precipitate  immediately  followed,  which,  upon  the  addition  of 
the  syr.  tolut.,  and  after  shaking,  slowly  arose  to  the  surface  of  the 
mixture. 
The  preparation  not  being  entirely  satisfactory,  a  few  experiments 
were  made  with  the  view  of  ascertaining  the  cause  of  precipitation. 
To  be  assured  that  the  fault  was  not  with  the  aqua  cinnam.  (which  had 
been  made  by  distillation  from  the  bark),  the  prescribed  quantity  each 
of  morph.  sulph.  and  potass,  bromid.  was  dissolved  separately  in  dis- 
tilled water,  and  the  two  solutions  mixed. 
The  same  result  was  obtained  as  when  aqua  cinnam.  was  used  as 
the  solvent. 
An  examination  was  next  made  of  the  morph.  sulph.  (Powers  & 
Weightman's),  which  proved  to  be  pure  sulphate  of  morphia.  The 
chances  for  the  potass,  brom.  to  prove  perfectly  faultless  now  looked 
rather  "slim."  A  solution  of  the  suspected  salt  (also  bearing  P.  & 
W.'s  label)  was  made  in  distilled  water,  and  tested  with  litmus  and 
turmeric  paper.  The  solution  gave  with  both  papers  a  decided  alka- 
line reaction,  which  fact  solved  the  mystery  of  the  precipitation  ;  for, 
as  is  well  known,  the  alkalies  and  their  carbonates  precipitate  mor- 
phia from  solutions  of  its  salts  ;  and  when  the  morph.  sulph.  solution 
came  in  contact  with  the  free  alkali  (potassa)  contained  in  the  potass, 
bromid.  solution,  the  precipitate  must  inevitably  have  taken  place. 
Several  samples  each  of  iodide  and  bromide  of  potassium  were 
tested  with  turmeric  paper,  and  in  every  instance  the  same  alkaline 
reaction  was  observed. 
The  foregoing  serves  to  show  how  serious  accidents  might  occur  by 
