﻿25.— 
  A 
  PRELIMINARY 
  NOTE 
  ON 
  THE 
  ACTION 
  OF 
  ACIDS, 
  SALTS 
  

   AND 
  ALKALIES 
  ON 
  THE 
  DEVELOPMENT 
  OF 
  CULICID 
  

   EGGS 
  AND 
  LARViE. 
  

  

  (Plate 
  XXXVI). 
  

  

  By 
  H. 
  N. 
  Sharma, 
  B.A. 
  

  

  The 
  experiments 
  referred 
  in 
  this 
  paper 
  were 
  made 
  with 
  the 
  object 
  of 
  

   determining 
  the 
  effect 
  of 
  various 
  chemicals 
  on 
  the 
  eggs 
  and 
  larva? 
  of 
  

   mosqiiitos, 
  the 
  immediate 
  purpose 
  being 
  to 
  gain 
  such 
  insight 
  as 
  would 
  

   lead 
  to 
  more 
  precise 
  series 
  of 
  experiments 
  with 
  more 
  definite 
  compounds. 
  

   While 
  I 
  was 
  investigating 
  the 
  effects 
  of 
  different 
  chemicals 
  upon 
  the 
  

   oviposition 
  of 
  mosquitos, 
  the 
  results 
  obtained 
  prompted 
  me 
  to 
  undertake 
  

   the 
  present 
  series 
  of 
  experiments 
  with 
  all 
  the 
  early 
  stages 
  of 
  Culicida). 
  

  

  It 
  occurred 
  to 
  me 
  that 
  attempts 
  might 
  be 
  made 
  to 
  ascertain 
  whether 
  

   there 
  was 
  any 
  connection 
  between 
  the 
  oviposition 
  and 
  the 
  development 
  

   of 
  eggs 
  and 
  larvae 
  of 
  Culicidse 
  with 
  various 
  chemicals. 
  

  

  The 
  chemicals 
  employed 
  are 
  : 
  — 
  

  

  Acids 
  : 
  Tannic, 
  Salicylic, 
  Boric, 
  Malic, 
  Butyric, 
  Acetic, 
  Lactie, 
  

   Tartaric, 
  Oxalic, 
  Sulphuric 
  and 
  Hydro-chloric. 
  

  

  Salts 
  : 
  Mercuric 
  chloride, 
  Potassium 
  permanganate, 
  Sodium 
  nitrate 
  

   Sodium 
  chloride. 
  Potassium 
  chloride, 
  Sodium 
  phosphate, 
  Sodium 
  

   sulphate. 
  Sodium 
  thiosulphate. 
  Potassium 
  bitartrate, 
  Sodium 
  

   tartrate. 
  Sodium 
  citrate, 
  Potassium 
  citrate 
  and 
  Sodium 
  oxalate. 
  

  

  Alkalies 
  : 
  Sodium 
  hydroxide. 
  Potassium 
  hydroxide 
  and 
  Calcium 
  

   hydroxide. 
  

  

  As 
  regards 
  the 
  selection 
  of 
  substances, 
  some 
  were 
  taken 
  up 
  with 
  

   reference 
  to 
  their 
  occurrence 
  in 
  natural 
  breeding 
  places, 
  while 
  others 
  

   had 
  reference 
  to 
  their 
  larvicidal 
  properties. 
  The 
  quantities 
  were 
  taken 
  

   not 
  at 
  random 
  but 
  in 
  the 
  majority 
  of 
  cases 
  in 
  definite 
  proportions 
  of 
  

   their 
  molecular 
  weights 
  ; 
  in 
  others 
  in 
  quantities 
  that 
  seemed 
  requisite 
  

   after 
  prolonged 
  experience. 
  For 
  our 
  present 
  purpose 
  it 
  would 
  be 
  un- 
  

   necessary 
  to 
  discuss 
  the 
  principles 
  underlying 
  these 
  selections. 
  The 
  

   "^bj 
  ect 
  of 
  this 
  paper 
  is 
  simply 
  to 
  present 
  in 
  a 
  brief 
  form 
  a 
  few 
  interest- 
  

   ing 
  facts 
  with 
  regard 
  to 
  the 
  behaviour 
  of 
  these 
  substances 
  towards 
  the 
  

   eggs 
  and 
  larvae 
  of 
  mosquitos. 
  

  

  The 
  experiments 
  with 
  Sodium 
  chloride 
  had 
  reference 
  to 
  the 
  practical 
  

   value 
  of 
  treatment 
  of 
  breeding 
  places 
  of 
  mosquitos 
  with 
  common 
  salt 
  

  

  ( 
  199 
  ) 
  

  

  o2 
  

  

  