360        DISINFECTANTS  IN  ARRESTING  CATTLE  PLAGUE. 
There  is  no  difficulty  in  admitting  that  the  infection  may  travel 
for  a  certain  limited  distance  through  the  air,  and  it  is  even 
likely  that  it  may  be  carried  longer  distances  by  fogs,  or  heavy 
vapors,  or  by  the  gases  of  putrid  decomposition  ;  but  it  appears 
in  the  highest  degree  improbable  that  the  germs  should  be  able 
to  retain  their  vitality  for  any  length  of  time  in  the  atmosphere. 
10.  Sufficient  data  do  not  at  present  exist  to  decide  whether 
the  germs  can  propagate  themselves  apart  from  the  animal. 
Viewing  them  as  of  the  nature  of  a  ferment,  it  is  not  impossible 
that  they  may  live  and  multiply  in  other  warm  liquids  besides 
the  blood  ;  but  the  most  reasonable  supposition  seems  to  be  that 
the  presence  of  decaying  organic  matter,  or  the  gaseous  emana- 
tions from  putrefying  dunghills,  preserves,  or  may  even  revive, 
the  expiring  vitality  of  germs  brought  by  men,  dogs,  birds,  ver- 
min, or  perhaps  the  wind  ;  whilst  the  same  causes  which  foster 
the  virus  cells — dirt,  overcrowding,  constant  re-breathing  of  their 
own  and  the  adjacent  animals'  breath,  an  insufficient  supply  of 
fresh  air,  the  presence  of  ammonia  and  other  gases  of  putrefac- 
tion, together  with  inappropriate  food — may  establish  a  deterio- 
rated state  of  body,  which  causes  the  animals  to  fall  ready  vic- 
tims at  the  first  approach  of  the  plague. 
The  existence  of  these  unfavorable  conditions  may  account 
for  the  fact  that  on  some  farms  the  disease  assumes  a  character 
so  virulent  that  no  remedy  or  preservative  is  of  any  avail 
against  it,  every  head  of  cattle  being  swept  off  one  after  another, 
each  attack  being  fatal  within  three  days  (15,  79,  80.)  In  the 
words  of  a  writer  in  the  "  Edinburgh  Review,"  u  a  single  spark 
of  infected  matter  accidentally  thrown  into  the  animal  economy, 
thus  reduced,  as  it  were,  to  a  touchwood  state,  fires  the  mass, 
which  burns  until  it  is  consumed." 
t 
Part  II. — On  Disinfectants  generally. 
11.  There  appears  as  yet  but  faint  hope  of  finding  a  cure  for 
the  disease,  and  even  were  medical  science  to  supply  that  great 
boon,  it  would  be  of  little  use  unless  supplemented  with  vigorous 
disinfecting  measures  ;  otherwise  it  would  be  like  attempting  to 
put  out  a  fire  fed  on  all  sides  with  inflammable  materials.  Dis- 
infection must,  therefore,  be  the  first  consideration,  and  should 
