AmMa0y,ri8P79arm' }  Gleanings  from  the  German  Journals.  247 
house-fly  became  helpless  in  ten  minutes,  a  mosquito  in  fifteen  minutes, 
a  flea  in  three  minutes. 
In  experimenting  upon  the  Coleoptera,  an  insect  as  nearly  the  size  of 
the  carpet-beetle  as  could  be  found  was  secured  in  Diabrotica  duodecim- 
punctata,  an  abundant  species  here.  It  was  easily  affected,  and  became 
helpless  in  twelve  minutes.  A  small  pinch  placed  in  the  jaws  of  a 
large  Carabus  stopped  locomotion  in  thirty  minutes.  The  Hem'iptera, 
owing  to  their  peculiarly  shaped  mouths,  were  enabled  to  vigorously 
resist  the  baleful  influence.  A  species  of  Coreus  was  active  at  the  end  of 
two  hours,  but  was  ultimately  overcome.  A  large-sized  katydid  was 
deprived  of  motion  at  the  end  of  ten  minutes  ;  Caloptenus  spretus  like- 
wise in  eighteen  minutes.  A  dragon-fly  {Libellulidce)  died  in  one  hour. 
Spiders  succumbed  in  one  hour  and  fifteen  minutes.  The  scent  from 
the  powder  did  not  produce  any  bad  effect  upon  insects  subjected  to  its 
odor  where  actual  contact  was  not  possible,  but  when  carried  to  the 
maxillae  or  mandibles,  the  effect  is  to  produce  complete  paralysis  of  the 
motor  nerves.  The  legs  are  paralyzed  in  regular  order,  commencing 
with  the  first  pair.  Insects  will  sometimes  live  for  days  in  this  condi- 
tion, but  death  ultimately  results  from  the  introduction  into  the  mouth 
of  the  smallest  quantity.  These  experiments  prove  that  all  insects 
having  open  mouth-parts  are  peculiarly  susceptible  to  this  powerful 
drug,  and,  as  a  result,  the  writer  does  not  hesitate  to  recommend  the 
powder  to  housekeepers  as  an  infallible  agent  in  destroying  the  carpet- 
beetle  and  preventing  its  ravages.  Twenty-five  cents'  worth  of  the 
powder  liberally  sprinkled  on  the  floor  before  putting  down  a  carpet, 
and  afterward  freely  placed  around  the  edges  and  never  swept  away, 
will  suffice  to  preserve  a  large-sized  carpet.  No  ill  effects  from  its  use 
need  be  feared  by  the  household,  since,  if  applied  in  this  way,  it  will 
be  only  poisonous  to  all  kinds  of  insects. — Am.  Nat.,  March,  1879. 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
By  Louis  von  Cotzhausen,  Ph.G. 
Unguentum  Hydrargyri. — Dr.  Godeffroy  states  that  the  thick 
liquid  residue  of  petroleum  refining,  if  mixed  with  a  little  paraffin  or 
ceresin  in  order  to  obtain  a  more  solid  consistence,  is  an  excellent  sub- 
stitute for  lard  and  suet  in  the  preparation  of  mercurial  ointment.  One 
gram  of  soft  paraffin  will  make  a  good  ointment  in  6  or  7  minutes  with 
