616         Fluorescences  of  Manganese  and  Bismuth.  {Am'&l™'5w*Tmm 
strongly  with  one  compound  of  a  metal  and  not  at  all  with  another 
compound  of  the  same  metal;  or  it  may  show  fluorescence  of  a  dif- 
ferent character  in  the  second  case.  Strongly  colored  substances  pre- 
vent the  fluorescence  of  active  substances  by  reason  of  their  strong  ab- 
sorptive power.  A  substance  may  behave  as  a  solvent  to  one  active 
substance;  and  also  behave  as  a  more  or  less  active  substance  itself 
when  mixed  with  a  third  substance.  When  two  active  substances  co- 
exist in  the  same  solvent  their  individual  fluorescences  are  reduced  in 
intensity,  but  their  spectral  character  is  not  altered.  Two  more  or 
less  active  substances  in  the  same  solvent  may,  however,  neutralize 
one  another.  A  substance  which  is  active  under  certain  conditions, 
but  is  inert  when  mixed  with  a  particular  solvent,  may  yet  reduce  the 
effect  of  a  substance  which  is  usually  active  with  this  solvent.  Fluo- 
rescence in  a  given  solvent  seems  as  a  rule  to  diminish  on  the 
addition  of  a  second  solvent  which  is  not  so  effective  with  the  active 
substance  as  the  first  solvent,  but  in  some  cases  this  effect  is  very 
slight. 
An  active  substance  generally  produces  a  double  fluorescence  with 
a  mixture  of  two  active  solvents,  but  with  certain  proportions  one  of 
the  fluorescences  diminishes  in  a  greater  ratio  than  the  quantity  of  the 
solvent  which  produces  it.  With  one  active  substance,  and  equivalent 
quantities  of  two  effective  solvents,  the  two  fluorescences  usually  are 
equal  in  intensity,  but  the  contrary  is  observed  in  certain  cases.  If 
two  substances  are  unequally  active  with  a  given  solvent,  and  the 
ratio  of  the  two  is  kept  constant  whilst  the  proportion  of  the  solvent 
is  gradually  increased,  it  is  possible  in  some  cases  to  observe  succes- 
sively (1)  the  effect  of  the  less  active  body  alone,  (2)  the  coexistence  of 
the  two  effects  with  increasing  predominance  of  the  effect  of  the  more 
active  substance.  When  the  proportion  of  the  more  active  substance 
is  increased,  its  effect  alone  is  observed  whatever  the  nature  of  the 
solvent.  Certain  fluorescences  which  are  masked  by  others  can  be 
seen  when  the  tube  is  heated,  or  by  observing  immediately  after  the 
cessation  of  the  electrical  discharge,  or  by  modifying  the  strength  of 
the  discharge. 
Cocaine  with  Lanolin. — Ernest  Wende  finds  lanolin  a  most  valuable 
base  for  cocaine  applications.  In  cases  of  burns  and  scalds  he  has  had  ex- 
cellent results  from  a  four  per  cent,  application  which  both  relieves  the  pain 
and  protects  the  surface  from  the  air. — Med.  Press  ;  St.  Louis  Courier  of  Med., 
July,  1887. 
