SENNA. 
78 
cathartate  of  ammonia,  prepared  from  cathartate  of  lead  by  my 
original  process,  and  the  mixed  cathartates,  prepared  according 
to  Dragendorfs  method  as  modified  by  myself.  Of  the  former 
nearly  pure  salt,  I  have  found  3|  grains  to  purge  fairly  as  to 
amount,  but  slowly  as  to  time,  and  with  considerable  griping. 
Of  the  latter,  7J  grains  purged  violently  with  much  griping  and 
sickness,  which  continued  through  the  greater  part  of  the  day, 
completely  knocking  the  patient  out  of  time  ;  4  grains,  would, 
I  think,  be  a  fair  dose.  It  should,  however,  be  given  in  conjunc- 
tion with  a  saline  and  an  aromatic  corrective  of  some  kind. 
With  phosphate  or  potassio-tartrate  of  soda  an  agreeable  and 
eifective  aperient  might  be  formed ;  possibly  the  cathartrate 
itself  might  be  modified  in  its  action  by  opium,  belladonna,  or 
hyoscyamus.  I  cannot  afiirm,  however,  that  the  active  principle 
has  a  more  unpleasant  action  than  the  raw  drug,  but  such  I 
should  expect  to  be  the  case. 
It  obviously  would  be  improper  to  combine  senna  with  any  of 
its  metallic  precipitants  should  such  be  desired,  which  is  not 
likely.  It  is  here  satisfactory  to  observe  that  the  cathartate  of 
magnesia  is  soluble,  and  that  the  old-fashioned  black  draught 
agrees  with  new-fashioned  science. 
The  effect  of  acids  on  senna  must  not  be  overlooked.  The 
mineral  acids  precipitate,  aided  by  heat  they  destroy,  its  active 
principle,  as  I  have  pointed  out  already.  The  organic  acids 
precipitate  it  from  its  aqueous  solution,  but  do  not  decompose  it 
on  boiling.  Here  then  is  a  very  important  distinction,  one  that 
saves  the  credit  of  such  preparations  as  the  old  Infusum  Sennas 
Limoniatum,  Decoctum  Tamarindorum  cum  Senna,  and  others  of 
the  class,  not  forgetting  the  much  used  Conf.  Sennse  Co. 
The  long-continued  action  of  heat  on  cathartates  exposed  to 
air  in  watery  solution,  is  to  decompose  them,  rendering  them 
inert.  Decoctions  and  extracts  of  senna  are  therefore  to  be  made 
with  proper  precautions,  or  preferably  abandoned  in  favor  of  the 
recent  and  quickly-made  infusion. 
Fermentation  either  of  the  infusion,  pure  and  simple,  or  of  the 
infusion  made  into  syrup  with  sugar,  decomposes  the  glucoside 
most  completely.    I  have  been  assured  by  a  constant  taker  of 
