246 
ON  PHOSPHORESCENCE. 
employed  arseniuretted  alcohol  for  twelve  years,  to  the  exclu- 
sion of  all  other  means  and  with  uniformly  good  results. 
It  follows  from  M.  Leprieur's  experience  that  living  insects, 
plunged  into  arseniuretted  alcohol,  and  removed  after  remain- 
ing there  for  twelve  hours  only,  increase  in  weight,  by  about  one- 
fourth  ;  insects,  therefore,  preserve  in  their  organs  an  amount  of 
arsenious  acid  about  equal  to  JL  of  their  own  weight,  a  quantity 
quite  sufficient  to  protect  them  from  destruction  by  larvae. 
According  to  M.  Leprieur,  the  employment  of  an  alcoholic  so- 
lution of  arsenious  acid  possesses  the  advantage  of  preventing,  in 
an  almost  absolute  manner,  the  ravages  of  larvae,  whilst  all 
other  means,  whatever  be  their  efficiency,  can  have  no  other 
result  than  the  actual  destruction  of  the  larvae  already  present 
in  a  collection,  without  having  any  power  to  protect  them  from 
future  ravages. — Chem.  News,  London,  from  Journal  de  Pharm. 
et  de  Chim.  vol.  xxxix. 
ON  PHOSPHORESCENCE. 
By  M.  De  Reichenbach. 
The  experiments  of  M.  De  Reichenbach  tend  to  prove  thit 
phosphorescence  is  a  usual  consequence  of  all  molecular  phe- 
nomena, and  not  the  result  of  combustion  or  oxidation.  Mr.  Phip- 
son  proved  this  last  point  some  time  ago,  when  he  showed  that 
dead  fishes  shine  in  the  dark,  even  under  water,  and  in  the  absence 
of  oxygen. 
According  to  M.  De  Reichenbach  there  is  phosphorescence 
during  fermentation  or  putrefaction,  crystallization,  evaporation, 
condensation  of  vapors,  the  production  of  sound  (vibrations 
therefore),  and  the  fusion  of  ice  ;  a  considerable  glow  is  remark- 
ed when  a  galvanic  pile  is  in  activity,  a  block  of  ice  in  fusion,  or 
a  solution  of  sulphate  of  soda  in  the  act  of  crystallizing  is  ob- 
served in  the  dark. 
The  human  body  itself  is  not  devoid  of  phosphorescence  :  in 
a  healthy  state  it  emits  a  yellow  glow ;  when  in  ill-health  the 
glow  becomes  red.  The  author  considers  that  this  observation 
may  possibly  be  of  use  in  diagnosis. 
To  perceive  these  phenomena  the  eye  ought  to  have  been  pre- 
viously rendered  sensitive  by  remaining  some  hours  in  perfect 
