484 
Disinfection  in  Medicine. 
Am.  Jour.  Pharm, 
Sept.,  1889. 
and  he  has  proposed  to  afford  protection  against  the  disease  by  culti- 
vating the  bacteria  artificially,  and  inoculating  with  the  poison  which 
they  produced  without  the  bacteria  themselves.  This  does  not  seem 
a  very  promising  method  of  treatment.'  Yet  there  was  no  reason  for 
despair,  for  facts  were  now  and  then  coming  to  light — the  bye-pro- 
ducts, as  it  were,  of  inquiries  dedicated  to  other  ends,  and  sometimes 
disregarded,  as  residual  phenomena  too  frequently  are — which  at  any 
rate  showed  how  greatly  the  virulence  of  any  bacillus  could  be  miti- 
gated by  slight,  and  what,  but  for  the  experiments  demonstrating  their 
effectiveness,  would  have  been  judged  perfectly  useless  differences 
in  the  conditions  of  their  development.  As  an  illustration  of  such 
mitigation  may  be  related  an  incident  which  occurred  in  the  course  of 
Dr.  Klein's  experiments  to  determine  the  influence  of  perchloride  of 
mercury  on  bacillus  anthracis  and  its  spores.  He  prepared  a  nutritive 
medium  of  agar-agar,  meat  extract,  peptone,  and  salt,  and  inoculated 
two  sets  of  tubes  containing  this  mixture  with  the  blood  of  a  guinea- 
pig,  dead  of  virulent  anthrax.  The  mixtures  in  the  two  sets  of  tubes 
were  made  with  similar  proportions  of  portions  of  the  very  same 
materials,  only  that  for  one  set  was  made  at  a  different  time  from  that 
of  the  other,  and  for  sterilization  purposes  one  happened  to  be  boiled 
longer  than  the  other.  'When  they  came  to  be  used  one  set  was 
darker  than  the  other.'  Anthrax  bacilli  grown  on  these  two,  and  then 
inoculated  into  guinea-pigs,  differed  greatly  in  virulence.  That  grown 
on  the  light-colored  mixture  killed  by  the  end  of  the  second  or  be- 
ginning of  the  third  day;  that  on  the  dark  mixture  not  earlier  than 
the  end  of  the  sixth,  or  even  of  the  seventh  day." 
Happily,  however,  the  theoretical  objections  to  the  method  have  not 
prevented  its  tentative  application  in  practice.  The  greatest  obstacle 
to  its  progress  has  been  the  phagocyte  theory  of  Metschnikoff,  who 
may  or  may  not  have  drawn  correct  deductions  from  what  he  saw,  but 
who,  at  all  events,  made  too  wide  an  application  of  his  theory  of  the 
destruction  of  germs  by  the  tissue  cells. 
"The  evidence  in  support  of  the  new  order  of  ideas  to  which  I 
have  referred  comes  from  various  quarters.  It  is  supplied  by  compe- 
tent men  working  nearly  simultaneously  with  different  chemical 
agents  and  different  methods  on  different  animals  suffering  from  dif- 
ferent infective  diseases,  and  yet  it  all  tends  to  establish  the  same  con- 
clusion, viz.,  the  possibility  of  affording  protection  against  various 
kinds  of  infection  by  the  employment  of  merely  chemical  agents. 
