512 
A  Use  for  the  Rare  Metals. 
(  Am.  Jour.  Pharm. 
\     October,  1895. 
bacteria,  many  of  which  are  perfectly  harmless  to  man.  The 
bacteria  discovered  in  the  corners  of  the  mouth  of  a  healthy  person, 
though  extremely  poisonous  and  dangerous  in  certain  conditions, 
can  be  classed  usually  with  the  harmless  varieties. 
But,  before  I  go  into  deeper  water — and  perhaps  I  ought  not  to 
go  deeper  in  an  article  at  this  time — it  has  been  made  manifest 
that  these  different  colored  micro-organisms  require  different  treat- 
ment, to  lead  to  their  annihilation.  The  several  species  capable  of 
throwing  off  a  reddish  coloring  matter — from  the  faint  pink  to  the 
deep  blood-red — may  require  quite  different  treatment  to  lead  to 
their  destruction  than  would  be  required  for  bacteria  producing  a 
blue  color — from  the  light  slate-blue  to  the  deep  blue  color  of  the 
thousand-fathomed  sea.  So  with  the  green,  the  violet  and  the 
brown,  as  well  as  the  other  colors. 
Some  labor  will  have  to  be  spent  in  determining  accurately  which 
are  injurious  to  human  life,  and  which  are  harmless  in  health ;  then 
to  determine  which  become  harmless  to  one  apparently  healthy,  and 
incapable  of  enduring  much  exposure.  Then  comes  the  task  of 
determining  which  are  most  injurious  when  disease  appears,  when 
disease  is  well  under  way ;  and  how  the  microbes  are  to  be  treated, 
if  treated  at  all,  when  the  disease  has  shown  signs  of  conquest. 
In  these  investigations  it  has  already  been  clearly  demonstrated 
that  the  products  of  the  botanical  world  are  futile,  no  matter  how 
administered,  when  certain  microbes  appear.  Dr.  Meade  Bolton,  in 
England,  followed  out  some  experiments  which  had  previously  been 
carried  on  by  others,  until  he  realized  that  there  are  certain  metals 
which  are  capable  of  destroying  microbes  in  contact  with  them. 
He  cultivated  certain  species  in  jelly,  spread  upon  a  plate ;  and  bits 
of  metal  were  dropped  upon  the  jelly  while  it  was  still  moist.  He 
found  that  any  metal  that  could  arrest  the  development  of  microbes 
destroyed  them ;  not  only  those  which  came  in  direct  contact  with 
the  metal,  but  other  microbic  life  for  a  narrow  space  around  the 
metal.  This  potentiality  varied,  not  only  with  the  kind  of  metal, 
but  with  the  species  of  microbes.  He  found  that  pure  gold  pro- 
duced no  effect ;  neither  did  pure  nickel,  nor  platinum,  nor  a  few 
other  metals  that  he  tried.  But  copper,  zinc  and  silver  were 
effective  in  some  instances,  though  cadmium  acted  quickly  and 
effectively  in  almost,  if  not,  every  instance.  The  learned  doctor 
observed  that  the  metals  which  affect  the  microbes  were  those  that 
