364  Infusion  of  Digitalis.  {Am- \^\$Stm' 
The  revised  formula  is  as  follows: 
Take  of  Digitalis  leaves,  bruised,   120  grains. 
Water,   141^  fluidounces. 
Ammonia  water,   90  minims. 
Alcohol,  •  .  1  fluidounce. 
Macerate  for  an  hour,  agitating  well  occasionally,  filter,  express 
residue,  wash  with  water,  and  filter,  to  make  14^  fluidounces.  Now, 
add  90  minims  of  ammonia  water,  1  fluidounce  of  alcohol,  and 
sufficient  water  to  make  the  volume  measure  1  pint. 
This  formula  has  been  used  for  nearly  three  years  past,  and  fre- 
quent inquiries  of  physicians,  as  to  the  medical  value  of  the  product, 
have  always  elicited  commendation.  Further,  Dr.  H.  C.  Wood, 
Professor  of  Materia  Medica  and  Therapeutics  in  the  University  of 
Pennsylvania,  writes  me  that  there  can  be  no  therapeutical  objec- 
tions to  the  use  of  ammonia  water  in  the  quantity  and  manner 
described.  If  the  formula  should  be  generally  adopted,  however,  the 
markedly  different  appearance  of  the  product  from  that  of  the  official 
formula  should  be  pointed  out  to  physicians.  The  infusion  is  of  a 
dark  red  brown  color  by  transmitted  light,  and  greenish  black  by 
refracted  light. 
The  official  product  usually  decomposes  in  three  or  four  days, 
precipitating.  With  the  ammoniated  product,  however,  there  is  no 
change  in  three  or  four  weeks  and  longer.  At  the  same  time  it  is 
always  best  to  make  the  product  extemporaneously.  It  may  be 
that  the  ammonia  water  exerts  its  preservative  influence  by  neutral- 
izing the  free  fatty  acids  in  digitalis.  There  are  a  number  of  acids 
present  in  digitalis  leaves — the  antirhinic  acid  of  Morin  (1845),  and 
the  digitoleic  acid  of  Kosmann,  with  which  the  digitaloic  acid  of 
Walz  is  probably  identical.  The  percentage  of  fixed  oil  in  digitalis 
is  relatively  high.  I  was  surprised  to  obtain  in  1887  about  5  percent. 
A  sample  is  here  exhibited.  Its  reaction  now  is  quite  acid.  Its 
reaction  when  first  obtained  was  not  observed. 
The  oil  in  question  was  obtained  from  Allen's  digitalis  leaves  by 
petroleum  benzin  extraction  and  spontaneous  evaporation,  in  Janu- 
ary, 1887.  The  oil,  or  rather  mixture,  as  there  is  evidently  present 
both  a  volatile  portion  and  a  fixed  oil,  is  a  dark  red  brown  trans-* 
parent  liquid  of  a  heavy,  persistent  narcotic  odor.  It  is  largely  sol- 
uble in  alcohol,  freely  soluble  in  ether  or  chloroform,  and  is  non- 
inflammable  (showing  absence  of  traces  of  petroleum  benzin).  It 
