86  Micro-Organisms  in  Preparations.  {AmFteb.^892ariL" 
vin  has  found  color-generating  organisms  in  orange-flower  and  rose 
waters,  but  only  when  the  preparations  have  been  exposed  to  the 
light. 
The  presence  of  algae  is  rarer  than  is  generally  credited,  and 
when  they  are  observed  they  are  found  to  be  species  of  Protococcus, 
Hcematococcus  and  Chlorococcus.  Light  is  essential  for  their  pro- 
duction, especially  in  the  case  of  green  algae ;  but  these  are  seldom 
observed,  the  condition  generally  corresponding  to  advanced  decom- 
position, the  fluid  having  masses  of  shiny  and  blackish  flocks  of  dead 
matter  floating  through  it. 
M.  Barnouvin  has  extended  his  researches  to  the  examination  of 
the  yellowish  deposit  which  is  formed  by  orange-flower  water.  This, 
as  far  as  we  can  remember,  has  never  been  described,  attention  being 
solely  directed  to  the  filamentous  growths  in  the  water  itself,  which 
are  composed  of  fungoid  remains,  spores  of  fungi,  and  the  living 
plants.  Examination  of  the  yellow  deposit  with  a  high-power 
objective  shows  it  to  consist  of  free  and  united  cells,  yellow  in  color, 
globular  in  shape  and  immovable.  They  are  apparently  a  true 
color-producing  bacterium,  and  have,, in  a  general  way,  the  character- 
istics of  Micrococcus  luteus,  Cohn.    (Bacteridium  luteumy  Schrceder.) 
The  existence  of  micro-organisms  in  certain  saline  solutions  has 
been  observed,  and  their  nature  more  or  less  definitely  determined 
by  different  observers.  Marchand  found,  ten  years  ago,  a  peculiar 
fungus  {Hygrocrocis  arsenicus)  in  arsenical  solutions,  and  a  few 
years  later  Barnouvin  published  a  list  of  solutions  of  salts  in  which 
similar  fungi  are  found,  the  list  including  cocaine  hydrochlorate^ 
quinine  hydrobromate,  pilocarpine  nitrate,  etc.  Purely  inorganic 
substances — e.  g.,  potassium  bromide  and  chlorate,  boracic  acid,  and 
magnesium  citrate,  are  equally  liable  to  attack.  In  all  these  cases  it 
is  proved  that  the  distilled  water  used  in  making  the  solutions  already 
contains  the  germs  or  the  young  organisms,  and  the  development 
corresponds  with  the  nature  of  salt.  The  organisms  are  rarely  green^ 
and  it  has  been  noticed  that  the  hygrocrocis  develops  in  these  solu- 
tions much  less  abundantly  than  in  hydrolates,  and  that  the  organ- 
isms are  frequently  sterile.  Bacteria  only  occur  sporadically  in  such 
media,  and  algae  are  also  rarely  found  ;  but,  strange  to  say,  Barnou- 
vin has  found  in  Boudin's  arsenical  solution  organisms  shaped  like 
a  turnip,  which  show  the  presence  of  a  true  diatom  of  the  tribe 
Navicules. 
