﻿PROCEEDINGS 
  OE 
  THE 
  FOURTH 
  ENTOMOLOGICAL 
  MEETING 
  lo9 
  

  

  Graph 
  4. 
  (Plate 
  XXX). 
  

   Represents 
  the 
  comparative 
  effects 
  of 
  HgCl 
  and 
  HgC12. 
  

  

  Graph 
  5. 
  (Plato 
  XXX). 
  

   Each 
  line 
  represents 
  the 
  average 
  of 
  three 
  observations. 
  

   Crosses 
  indicate 
  death 
  points. 
  

  

  Quantity 
  of 
  water 
  used 
  in 
  each 
  experiment 
  100 
  c. 
  c. 
  

   Quantity 
  of 
  HgCl, 
  when 
  used, 
  0-001 
  gram. 
  

  

  Graph 
  G. 
  (Plate 
  XXX). 
  

   Comparative 
  effects 
  of 
  HgCl 
  and 
  Kcrosinc. 
  

   Vertical 
  line 
  represents 
  longevity 
  of 
  larva 
  in 
  hours. 
  

  

  Horizontal 
  line 
  represents 
  time 
  in 
  hours 
  that 
  had 
  passed 
  since 
  the 
  introduction 
  ot 
  

   the 
  larvicide. 
  

  

  Cross 
  indicates 
  death 
  point. 
  

  

  Quantity 
  of 
  Kerosine 
  used, 
  2 
  minims. 
  Quantity 
  of 
  HgCl 
  used, 
  0-001 
  gi-am. 
  

  

  The 
  Graph 
  represents 
  the 
  average 
  of 
  three 
  observations. 
  

  

  N. 
  B. 
  — 
  After 
  the 
  80th 
  hour 
  Kerosine 
  failed 
  to 
  kill. 
  

  

  Did 
  you 
  try 
  these 
  experiments 
  witli 
  Anophelines 
  I 
  I 
  understand 
  it 
  Major 
  Christo- 
  

   is 
  the 
  Mercurous 
  Chloride 
  on 
  the 
  surface 
  fihu 
  that 
  acts, 
  not 
  the 
  sohition. 
  ^ 
  ^ 
  ' 
  

   If 
  this 
  is 
  so, 
  a 
  Stegomyia 
  larva 
  feeding 
  at 
  the 
  bottom 
  should 
  not 
  show 
  the 
  

   effects 
  as 
  well 
  as 
  the 
  Anopheline. 
  

  

  I 
  did 
  not 
  experiment 
  with 
  Anophelines. 
  With 
  regard 
  to 
  Stegomyia, 
  Mr. 
  Sen. 
  

   as 
  the 
  pupae 
  were 
  generally 
  unaffected, 
  it 
  seemed 
  likely 
  that 
  the 
  salt 
  

   operated 
  orally 
  a;nd 
  not 
  cutaneously. 
  

  

  I 
  conducted 
  some 
  experiments 
  on 
  the 
  efficacy 
  of 
  Paraiormol, 
  the 
  Mr. 
  Iyengar, 
  

   original 
  work 
  on 
  which 
  was 
  done 
  by 
  M. 
  Koubaud 
  at 
  Paris. 
  Paraformol 
  

   is 
  a 
  solid 
  form 
  of 
  formaline, 
  is 
  finely 
  powdered 
  and 
  distributed 
  on 
  the 
  

   surface 
  of 
  the 
  water. 
  The 
  Anopheline 
  larvae 
  devour 
  the 
  powder 
  and 
  

   are 
  killed 
  in 
  the 
  course 
  of 
  fifteen 
  to 
  thirty 
  minutes. 
  But 
  the 
  pupae 
  of 
  

   Anophelines 
  and 
  the 
  larvae 
  of 
  Culicines 
  are 
  not 
  at 
  all 
  affected. 
  

  

  The 
  powder 
  is 
  insoluble 
  in 
  water, 
  and 
  it 
  either 
  floats 
  on 
  the 
  surface 
  

   or 
  sinks 
  if 
  it 
  is 
  in 
  bigger 
  particles. 
  There 
  is 
  no 
  likelihood 
  of 
  the 
  pow- 
  

   der 
  being 
  taken 
  in 
  by 
  man 
  and 
  even 
  if 
  taken 
  it 
  is 
  not 
  very 
  harmful. 
  If 
  

   people 
  are 
  particularly 
  scrupulous 
  about 
  it, 
  a 
  filtering 
  of 
  the 
  water 
  

   through 
  a 
  piece 
  of 
  cloth 
  would 
  get 
  rid 
  of 
  the 
  paraformol. 
  I 
  have 
  tried 
  

   such 
  water 
  and 
  have 
  found 
  it 
  perfectly 
  harmless 
  and 
  even 
  without 
  smell. 
  

   A 
  single 
  gram 
  of 
  Paraformol 
  would 
  be 
  enough 
  to 
  spread 
  over 
  several 
  

   square 
  metres 
  of 
  water 
  surface. 
  

  

  I 
  attempted 
  to 
  keep 
  the 
  salt 
  particle 
  afloat 
  by 
  means 
  of 
  a 
  viscous 
  Mr. 
  Sen. 
  

   oil. 
  

  

  If 
  a 
  very 
  viscous 
  oil 
  is 
  used 
  to 
  contain 
  the 
  mercurous 
  chloride 
  the 
  oil 
  Mr. 
  Fletcher, 
  

   will 
  not 
  spread 
  and 
  you 
  would 
  use 
  a 
  great 
  deal, 
  thus 
  enhancing 
  largely 
  

   the 
  cost. 
  

  

  