F arieties. 
Am.  Jour  Pharrn„ 
June,  1880. 
Potassium  chloride  in  potassium  bromide  is  detected,  by  the  same  author, 
by  dissolving  O'l  gram  powdered  potassium  bromide  in  2  or  3  cc.  of 
water,  mixing  well  with  a  solution  of  0*i6  gram  of  silver  nitrate  in  3  or 
4  cc.  of  water,  adding  10  or  12  cc.  of  solution  of  ammonium  carbonate^ 
shaking  frequently  for  about  10  minutes,  and  filtering,  returning  the  filt- 
rate to  the  filter  until  it  passes  entirely  clear.  To  3  or  4  cc.  of  the  clear 
filtrate  nitric  acid  is  then  added,  drop  by  drop,  until  neutralized,  when^ 
in  case  potassium  bromide  alone  was  present,  the  liquid  remains  clear, 
while  in  the  presence  of  silver  chloride  it  will  be  opalescent  or  cloudy, 
according  to  the  percentage  of  chloride  present. 
Hydrochloric  acid  in  hydrohromic  acid  may  be  detected  in  a  similar  man- 
ner, using  2  or  3  drops  of  the  acid,  7  to  10  drops  of  solution  of  silver 
nitrate,  adding  about  1  o  cc.  of  solution  of  ammonium  carbonate,  shakings 
macerating,  filtering  and  supersaturating  with  nitric  acid. — Ihid.^  p.  85-87. 
Arsenic  in  hydrochloric  acid  is  detected  by  Hager's  modification 
of  Bettendorf's  method  by  dropping  the  acid  in  very  small  drops  on 
thick  tin-foil,  setting  aside,  and  exposing  to  a  heat  of  from  50°  to 
90°C.  Concentrated  acid  and  acid  diluted  with  an  equal  bulk  of  water^ 
and  containing  ^-qVlT  To'u^TnT  arsenic,  immediately  turn  brown  011 
the  tin-foil;  when  diluted  with  8  or  10  times  its  bulk  of  water  the  reac- 
tion is  considerably  slower.  A  very  dilute  acid,  containing  2^0^^-5-0^  arse- 
nic, dropped  on  tin-foil  in  small  drops,  and  placed  in  a  lukewarm  place^ 
yielded  steel-colored  spots.  The  test  is  not  reliable  for  an  acid  con- 
taining but  ij^iy^ou  arsenic. — Ibid.^  March  25,  1880,  p.  10 1. 
VARIETIES. 
Duboisia  Sulphate. — S.  D.  Risley,  M.D.,  Lecturer  on  Ophthalmoscopy  in  the 
University  of  Pennsylvania,  in  an  interesting  article  in  the  "Amer.  Jour.  Med.  Sci.," 
April,  1880,  "On  the  relative  value  of  the  sulphates  of  atropia  and  of  duboisia  in 
ophthalmic  practice,"  states  that  the  following  conclusions  seem  justifiable: 
1.  That  in  solutions  not  stronger  than  two  grains  to  the  ounce  duboisia  is  free 
from  danger. 
2.  That  the  two-grain  solution  of  Duboisia  sulphate  more  rapidly  paralyzes  the- 
ciliary  muscle  than  a  four-grain  solution  of  atropia  sulphate. 
3.  That  the  duration  of  its  effect  is  less  than  half  that  of  atropia. 
4.  That  the  preparations  now  in  the  market  are  more  liable  to  irritate  the  con 
junctiva  than  neutral  solutions  of  the  sulphate  of  atropia. 
5.  That  in  the  treatment  of  inflammations  of  the  eye  duboisia  is  quite  as  useful  as 
atropia,  and  therefore  may  be  used  as  a  substitute. 
