Siccative  powders,  like  starch  and  steatite,  are  known  to  be  useful  in
surgery.  Many  epidemics  have  suddenly  ceased  when  a  dry  season
has  set  in.
Both  Koch  and  Klein  have  proved  that  the  spores  of  most  of  the
common  species  of  bacteria  resist  drying  for  an  indefinite  period.
Klein  kept  the  spores  of  various  potato  bacilli — e.g.,  Peronospora
infestans  (the  potato  blight).  Bacillus  anthracis,  the  hay  bacillus,  and
those  of  scurf  and  jequirity,  in  culture  tubes  of  agar  agar  in  a  per-
fectly dry  state  —i.e.,  in  a  closed  bell-jar  over  oil  of  vitriol — until  the
medium  had  dried  up  to  a  thin  shrivelled  film  ;  and  yet,  even  after
two  years  and  a  half,  on  inoculating  fresh  materials  from  the  above
tubes,  typical  and  good  growths  were  obtained.  On  the  other  hand,
non-spore-bearing  bacteria — e.g.,  various  species  of  Staphylococcus,
Streptococcus — bacilli  of  typhoid,  swine  fever,  swine  erysipelas,  Koch's

*  Thirteenth  Be  port  of  Med.  Off.  of  Privy  Council.
fCentr.f.  Bakteriologie,  1888,  vol.  iv.,  p.  547.  :J/6Jd.,  p.  547.
%Ze\tachr.  f.  Hyg.,  1886,  I.,  p.  302.  See  also  Heyroth,  Arbeit.  Kais.  Oeaund.,
vol.  iv.,  1888.
2


18  DISINFECTION   AND   DISINFECTANTS.
