148 
Homatropine, 
f  Am.  Jour.  Pharm, 
1      April,  1882. 
Crystal  of  Homatro- 
pine  hydrobromate. 
iodine  in  potassium  iodide  yellow  crystals  together  with  a  black  oil. 
Platinic  chloride  produces  in  the  concentrated  solution  an  aniorj)hous 
precipitate,  and  from  the  filtrate  handsome  needles  are  obtained  on 
evaporation.  # 
Homatropine-hydrohro'niatej  CjgHgiNOj. I IBr, 
may  be  readily  obtained  in  the  crystalline  form, 
and  may  therefore  be  directly  prepared  from 
the  unpurified  base.  The  crystalline  mass  thus 
obtained  may  be  recrystallized  from  water, 
when  the  pure  salt  is  obtained  in  large,  wart- 
like aggregations  of  crystals. 
The  crystals  have  the  form  of  rhombic 
prisms  with  irregularly  developed  pyramidal 
surfaces,  as  shown  in  the  figure.  The  salt  is  not 
hygroscopic,  is  soluble  in  ten  parts  of  water,  and 
the  solutions  do  not  readily  undergo  change. 
The  physiological  action  of  homatropine  hydrobromate  has  already 
been  briefly  alluded  to  in  this  journal,  1880,  p.  629,  and  1881,  p.  .70. 
To  recall  the  statement  of  Mr.  John  Tweedy  and  Dr.  Sydney  Ringer,  as 
contained  in  the  "Lancet,^'  May  22, 1880,  and  abstracted  in  the  "  Amer. 
Jour.  Med.  Sciences,''  1880,  p.  267,  it  is  a  bland  and  efficient  mydri- 
atic, rapid  in  its  action  and  of  comparatively  short  duration.  More 
recently  the  action  of  the  salt  has  been  made  the  subject  of  a  large 
number  of  careful  physiological  experiments  by  Dr.  S.  D.  Risley,^  of 
this  city,  whose  conclusions  as  to  its  value  may  be  summarized  in  his 
own  words : 
"1.  That  homatropine  hydrobromate  in  solutions  of  two,  four  and 
six  grains  to  the  ounce  is  competent  to  paralyze  the  accomodation. 
"  2.  That  in  from  sixteen  to  thirty  hours  this  paralysis  entirely  dis- 
appears. 
"  3.  That  dilation  of  the  pupil  accompanies  the  paralysis  and  is 
more  persistent,  the  probable  duration  being  forty-eight  hours. 
"4.  That  it  is  no  more  liable  to  produce  conjunctival  irritation 
than  atropine  or  duboisine. 
^'  5.  That  it  produces  far  less  constitutional  disturbance  than  either 
of  the  old  mydriatics." 
1  "The  value  of  homatropine  hydrobromate  in  ophthalmic  practice"  in 
Amer.  Jour.  Med.  Sciences,"  1881,  p.  113—119. 
