Am.  Jour.  Pharm,  \ 
May,  1883.  / 
Disinfectants. 
275 
DISINFECTANTS. 
By.  11.  Koch. 
Tlie  mode  of  action  of  individual  disinfectants  lias  not  been  sutticiently 
investigated,  because  of  our  incomplete  knowledge  of  the  infectious  matter. 
An  (efficient  disinfectant  ought,  in  the  author's  opinion,  to  kill  all  living 
organisms  and  render  all  germs  innoxious  within  twenty-four  hours.  To 
test  a  disinfectant  thoroughly,  its  action  must  be  tried  on  all  disease-produc- 
ing matter,  and  under  conditions  exactly  similar  to  those  in  which  it  is 
used  in  practice.  Thus  a  disinfectant  which  does  not  kill  fungi  would  be  of 
no  use  in  contagious  skin  diseases,  whilst  one  which  did  not  destroy  bacteria 
would  be  inefficient  in  diseases  caused  by  these  organisms.  The  author  has 
investigated  the  action  of  disinfectants  on  bacteria.  In  these  experiments, 
he  has  taken  great  care  in  the  cultivation  of  bacteria,  selecting  those  which 
are  seldom  found  in  the  air.  Experiments  on  the  development  of  bacteria 
were  made  on  solid  nutritious  substances.  The  chief  points  observed  are — 
1.  If  all  the  organisms  are  killed.  For  this  it  is  sufficient  to  note  the  action 
on  the  most  persistent,  viz.,  the  bacilli  spores.  2.  The  facility  with  which 
the  development  of  micro-organisms  in  favorable  nutritive  solutions  is 
prevented. 
Carbolic  acid  is  almost  without  action  on  spores  of  Anthrax  bacilli,  c.  (j., 
the  bacilli  spores  retained  their  vitalitj'^  after  being  five  days  in  a  2  per  cent, 
solution,  and  in  another  experiment  fifteen  days  in  a  1  per  cent.  It  is, 
however,  destructive  to  the  living  micro-organism,  for  1  gram  of  pure  car- 
bolic acid  can  completely  prevent  the  development  of  Ant Jir ax  bacilli  in  850 
cc.  of  a  nutritive  solution,  and  even  shows  a  marked  effect  in  1250  grams. 
Its  action  on  other  bacteria  is  less  marked.  Carbolic  acid  in  the  form  of 
vapor  does  not  effect  the  germinating  power  of  bacilli  spores  at  the  ordinary 
temperature,  even  after  being  in  contact  with  them  1^  months,  but  at  55°, 
in  half  an  hour  many  of  the  spores  are  destroyed,  in  three  hours  scarcely 
any  germinating  i^ower  is  discernable,  whilst  after  five  or  six  hours  their 
destruction  is  complete.  Baising  the  temperature  does  not  increase  the 
activity.  Carbolic  acid  vapor  can  only  be  conveniently  used  for  small 
objects. 
The  above  results  are  obtained  with  aqueous  solutions  of  carbolic  acid. 
Solutions  in  oil  or  alcohol  do  not  show  any  antiseptic  properties ;  this  is 
also  the  case  with  other  disinfectants,  c.  salicylic  acid,  thymol,  etc., 
except  when  they  are  used  with  substances  containing  water,  such  as  flesh, 
etc.,  when  some  of  the  disinfectants  become  active. 
SuljihurouH  acid,  either  alone  or  mixed  with  water  or  steam,  does  not  dis- 
infect dry  objects.  If,  on  the  other  hand,  the  object  is  first  moistened  with 
sulphurous  acid  and  then  treated,  brisk  action  is  observed ;  it  does  not, 
however,  destroy  all  germs.  Its  disinfecting  action  is  thus  uncertain,  and 
is  not  to  be  depended  on. 
Amongst  many  others,  zinc  chloride  and  glycerol  sir q  proved  to  be  without 
effect.  In  fact  the  only  effective  dlMnfectants  (see  above)  besides  chlorine, 
bromine,  and  iodine,  are  corrosive  sublimate,  osmic  acid,  and  jwtassium 
permanganate.    The  last  mentioned  only  acts  in  strong  solutions  (5  per 
