416 
Theory  of  Disinfectants. 
/  Am.  Jour.  Pharm. 
\     Sept.  1, 1871. 
In  order  to  test  the  accuracy  of  the  view  thus  enunciated,  I  selected 
a  substance  of  which  the  albumen-coagulating  power  was  well  known, 
and  examined  it  with  regard  to  its  antiseptic,  and,  therefore,  disin- 
fectant properties.  The  substance  chosen  was  nitro-muriatic  acid, 
which  has  long  been  in  use  as  a  test  for  albumen  in  urine.  The  ex- 
periments were  conducted  as  follows  : 
a.  Two  samples  of  fresh  healthy  urine,  passed  at  the  same  time, 
each  measuring  about  one  ounce,  were  placed  side  by  side.  To  one 
of  them  six  drops  of  strong  nitro-muriatic  acid  were  added.  In  a  few 
days,  the  unacidified  specimen  was  covered  with  a  thick  crust  of  mould; 
while  that  to  which  the  acid  had  been  added  was  unaltered,  except 
by  a  slight  darkening  of  color  and  deposition  of  crystals  of  uric  acid. 
h.  Some  fresh  meat  was  pounded  into  an  emulsion  with  water, — 
the  whole  divided  into  two  equal  portions  of  about  six  drachms  each. 
To  one  of  them  six  drops  of  strong  nitro-muriatic  acid  were  added,  as 
in  the  former  case.  In  a  day  or  two,  the  unacidified  sample  was  quite 
putrid  and  offensive ;  while  that  to  which  the  acid  had  been  added 
retained  the  smell  of  fresh  meat,  and  continues  to  do  so  still,  after  the 
lapse  of  nearly  a  month. 
I  now  proceeded  to  test  some  of  the  salts  commonly  used  as  disin- 
fectants, with  respect  to  their  possession  of  this  power  of  coagulating 
albumen.  The  examination  was  conducted  thus  :  One  part  of  the 
salt  to  be  tested  was  dissolved  in  one  thousand  parts  of  distilled  water, 
and  the  solution  was  mixed  thoroughly  with  the  fresh  white  of  egg. 
The  salts  examined  were  iron-alum,  sesquichloride  of  iron,  common 
alum,  chloride  of  zinc  and  nitrate  of  lead.  Coagulation  followed  im- 
mediately in  every  instance.  In  one  or  two  cases  the  dilution  was 
carried  much  further, — one  part  of  the  salt  to  three  or  four  thousand 
of  water.    Here,  too,  coagulation  followed  in  one  or  two  seconds. 
It  may  be  remarked,  in  passing,  that  the  haemostatic  action  of  the 
iron-salts  is  probably  to  be  attributed  in  great  measure  to  this  faculty 
of  coagulating  albumen,  exercised  upon  the  serum  of  the  blood. 
The  attempt  to  obtain  similar  results  from  the  sulphites  entirely 
failed.  They  appeared,  indeed,  to  retard  coagulation  by  other  re- 
agents. The  coagulating  power  of  sulphurous  acid  was  faint  and  ill 
defined. 
If  we  review  the  evidence  now  before  us,  we  shall  find  that  it  stands 
thus  : 
We  start  with  two  assumptions, — the  first  justified  by  recent  re- 
