430         DISINFECTANTS  IN  ARRESTING  CATTLE  PLAGUE. 
then  some  smell  of  cheese,  but  it  required  a  considerable  quantity 
of  chlorine  to  kill  the  mites.  Exactly  the  same  experiment  was 
now  repeated,  only  leaving  out  the  sulphuretted  hydrogen  and 
cheese.  The  chlorine  now  had  nothing  to  divert  its  energy 
from  the  cheese  mites,  which  were  consequently  killed  before 
one-fourth  the  quantity  of  chlorine  used  in  the  first  instance  had 
been  added. 
Again,  oxidizing  disinfectants  possess  little  if  any  continuous 
action.  What  they  attack  is  destroyed  perfectly,  but  what  they 
leave  has  no  special  resistance  to  decomposition  conferred  upon 
it.  They  remove  the  products  of  decomposition,  but  they  do  not 
take  away  the  power  of  further  putrefaction. 
In  addition  to  these  general  faults  possessed  by  oxidizing 
disinfectants,  the  following  special  objections  may  be  urged 
against  chlorine  and  ozone  : — 
26,  Chlorine. — This  agent  requires  to  be  liberated  in  the 
gaseous  state  by  a  chemical  process.  This  at  the  outset  is  an 
objection,  for  experience  shows  that  farm  laborers  are  not  fit 
persons  to  be  trusted  with  the  performance  of  a  chemical  experi- 
ment involving  the  use  of  corrosive  acids.  The  smell  of  chlorine 
is  very  irritating  to  the  lungs  of  diseased  or  convalescent  ani- 
mals ;  and  instances  have  come  to  my  knowledge  in  which 
permanent  injury  has  resulted  from  its  employment.  More- 
over, the  cattle  dislike  it  much.  Its  action  is  more  energetic 
upon  the  valuable  constituents  of  the  manure  than  upon  septic 
germs* :  it  rapidly  attacks  ammoniacal  compounds,  the  urea 
and  hippuric  acid,  and  considerably  reduces  the  manurial  value 
of  farm-yard  stuff.  If  much  ammonia  is  present  in  the  shed, 
chloride  of  nitrogen  is  likely  to  be  formed,  the  vapor  of  which, 
even  in  minute  quantities,  is  painfully  distressing  to  the  eyes  of 
cattle  and  their  attendants.  Another  great  objection  is  that 
gaseous  chlorine,  being  absorbed  by  the  whitewash,  soon  forms 
chloride  of  calcium,  (21,  28),  the  deliquescence  of  which  will 
*  I  find  it  recorded  in  the  Medical  Record  for  March  15, 1866,  that  Dr. 
J.  P.  Loines,  of  New  York,  as  the  result  of  a  series  of  experiments,  has 
come  to  the  conclusion  that  chlorine,  in  quantity  sufficient  to  be  irrespir- 
able,  has  no  effect  upon  the  infecting  property  of  the  vaccine  crust;  and, 
reasoning  from  this  analogy,  he  is  of  opinion  that  the  same  is  the  case  with 
the  virus  of  variola. 
