166 
ON  THE  ORIGIN  OF  FERMENTS. 
On  that  occasion  I  showed,  in  a  manner  that  has  been  con- 
tested only  in  appearance — First,  that  the  solid  particles  con- 
veyed in  the  atmospheric  air  were  the  origin  of  all  the  vegetable 
and  animal  productions  peculiar  to  the  fluid  in  question.  Sec- 
ondly, that  these  particles,  examined  under  the  microscope,  are 
amorphous,  dusty  atoms,  constantly  associated  with  certain 
corpuscles,  whose  form,  volume  and  structure  show  that  they 
are  organized  after  the  manner  of  the  ova  of  Infusoria  or  of  the 
spores  of  the  Mucedinea. 
I  am,  at  present,  in  a  condition  to  extend  the  assertions  con- 
tained in  the  communication  of  the  6th  February  to  two  sub- 
stances, still  more  alterable  than  the  sugared  water  mixed  with 
albuminous  matters  which  had  been  more  particularly  the  subject 
of  my  former  experiments.  I  now  speak  of  "  milk"  and 
'Murine."  The  details  of  the  results  derived  from  these  two 
fluids  will  show,  as  I  hope,  the  kind  of  future  in  store  for  this 
department  of  study. 
I  introduce  about  100  cubic  centimeters  of  recent  urine  into  a 
a  flask  capable  of  containing  250  cubic  centimeters.  The  drawn- 
out  neck  of  the  flask  communicates  with  a  platinum  tube,  heated 
to  redness.  The  liquid  is  made  to  boil  for  two  or  three  minutes, 
and  then  allowed  to  cool.  When  refilled  with  air,  which 
has  been  subjected  to  a  red  heat,  the  flask  is  hermetically 
closed. 
The  flask,  under  these  conditions,  may  remain  for  an  indefinite 
time  in  a  stove,  at  a  temperature  of  30^^  C,  without  its  under- 
going any  alteration.  After  the  lapse  of  a  month  or  six  weeks, 
I  cause  a  small  quantity  of  amianthus  charged  with  the  atmos- 
pheric dust  to  fall  into  the  flask,  the  mode  in  which  this  is  ef- 
fected being  precisely  that  described  in  the  Oomptes  Rendus  of 
the  6th  of  February.  The  neck  of  the  flask  being  then  again 
hermetically  closed,  the  apparatus  is  replaced  in  the  stove. 
In  order  to  be  sure  that  the  manipulation  to  which  the  flask 
is  submitted,  for  the  introduction  of  the  atmospheric  dust,  does 
not  itself  in  any  way  afl'ect  the  result  of  the  experiment,  I  pre- 
pare a  second  flask  similar  to  the  other  ;  only  that,  instead  of 
allowing  amianthus  charged  with  atmospheric  dust  to  fall  into 
it,  I  substitute  the  same  amianthus  previously  calcined  for  some 
moments  before  its  introduction  into  the  flasko 
