﻿356 
  C. 
  F. 
  M. 
  SWYNNERTON. 
  

  

  It 
  seemed 
  that 
  even 
  a 
  larger 
  measure 
  would 
  be 
  on 
  the 
  safe 
  side, 
  namely 
  the 
  clearing 
  

   of 
  villages 
  throughout 
  the 
  tsetse-infected 
  areas 
  surrounding 
  that 
  of 
  the 
  outbreak, 
  

   and 
  particularly 
  along 
  such 
  routes 
  as 
  that 
  to 
  the 
  salt 
  at 
  Lake 
  Eyasi, 
  but 
  where 
  game 
  

   is 
  abundantly 
  present 
  clearing 
  may 
  be 
  quite 
  unnecessary, 
  and 
  one 
  does 
  not 
  wish 
  

   to 
  harass 
  unduly 
  people 
  whose 
  co-operation 
  is 
  essential 
  to 
  the 
  success 
  of 
  our 
  more 
  

   necessary 
  measures. 
  The 
  measure 
  I 
  suggest 
  on 
  page 
  367 
  might 
  suffice. 
  

  

  5. 
  The 
  Hastening 
  of 
  the 
  Extermination 
  of 
  the 
  Tsetses 
  already 
  infected. 
  

  

  Destruction 
  by 
  fire. 
  — 
  It 
  is 
  probable 
  that 
  a 
  large 
  number 
  of 
  tsetses 
  in 
  any 
  case 
  

   fail 
  to 
  survive 
  the 
  hard 
  conditions 
  of 
  the 
  height 
  of 
  the 
  dry 
  season, 
  and 
  these 
  conditions 
  

   would 
  be 
  intensified 
  by 
  thorough 
  burning. 
  

  

  The 
  question 
  arose 
  whether 
  we 
  should 
  sacrifice 
  the 
  anticipated 
  effect 
  of 
  a 
  really 
  

   late 
  fire 
  on 
  the 
  bush 
  and 
  the 
  more 
  exposed 
  puparia 
  and 
  try 
  to 
  produce 
  an 
  early 
  effect 
  

   on 
  the 
  fly 
  on 
  the 
  wing 
  — 
  which, 
  if 
  cyclical 
  transmission 
  were 
  an 
  active 
  factor, 
  might, 
  

   in 
  thousands, 
  remain 
  capable 
  of 
  infecting 
  people 
  or 
  perhaps 
  the 
  game. 
  The 
  matter 
  

   was 
  really 
  decided 
  by 
  the 
  certainty 
  (confirmed 
  by 
  information 
  from 
  the 
  Senior 
  Com- 
  

   missioner, 
  Tabora, 
  to 
  the 
  same 
  effect) 
  that 
  it 
  would 
  be 
  impossible 
  this 
  year 
  to 
  preserve 
  

   the 
  grass 
  after 
  the 
  end 
  of 
  August. 
  Evacuation 
  was 
  to 
  take 
  place 
  in 
  August, 
  and 
  it 
  

   was 
  decided 
  that 
  the 
  grass 
  should 
  be 
  kept 
  unburnt, 
  if 
  possible, 
  till 
  the 
  31st 
  August. 
  

   I 
  have 
  since 
  heard 
  that 
  it 
  was 
  not 
  possible 
  to 
  do 
  this 
  even 
  till 
  August. 
  

  

  I 
  have 
  always 
  foreseen 
  that 
  it 
  will 
  take 
  three 
  or 
  four 
  years 
  fully 
  to 
  convince 
  the 
  

   natives 
  generally 
  that 
  the 
  Government 
  is 
  in 
  earnest 
  in 
  this 
  matter 
  and 
  to 
  secure 
  

   their 
  co-operation. 
  

  

  Catching 
  the 
  flies 
  with 
  nets. 
  — 
  It 
  seemed 
  likely 
  that 
  with 
  man 
  as 
  the 
  special 
  object 
  

   of 
  their 
  continuous 
  attention, 
  the 
  majority 
  of 
  the 
  infected 
  flies 
  should 
  at 
  a 
  given 
  

   time 
  be 
  found 
  about 
  infected 
  villages 
  in 
  the 
  bush 
  and 
  on 
  the 
  bush 
  paths 
  between 
  

   them. 
  Smart 
  local 
  natives 
  were 
  engaged 
  and, 
  having 
  been 
  trained 
  to 
  catch 
  flies, 
  

   were 
  returned 
  to 
  catch 
  in 
  their 
  own 
  localities 
  in 
  specified 
  places 
  until 
  after 
  the 
  fires 
  

   or 
  up 
  to 
  evacuation. 
  It 
  was 
  hoped 
  that 
  a 
  system 
  of 
  rewards 
  would 
  ensure 
  their 
  

   carrying 
  out 
  the 
  work 
  with 
  some 
  thoroughness 
  and 
  that 
  the 
  large 
  crop 
  of 
  infections 
  

   which 
  (on 
  native 
  information) 
  appeared 
  to 
  take 
  place 
  " 
  at 
  hoeing 
  time 
  " 
  might 
  even 
  

   be 
  to 
  some 
  extent 
  anticipated. 
  At 
  any 
  rate, 
  in 
  view 
  of 
  the 
  considerable 
  captures 
  

   made 
  by 
  the 
  natives 
  with 
  myself 
  at 
  one 
  or 
  two 
  such 
  spots 
  of 
  flies 
  a 
  great 
  many 
  of 
  

   which 
  should 
  have 
  been 
  infected 
  if 
  cyclical 
  transmission 
  was 
  present, 
  it 
  seemed 
  

   well 
  worth 
  attempting 
  this 
  disinfection 
  of 
  the 
  village 
  flies 
  now 
  that 
  the 
  accomplished 
  

   segregation 
  of 
  infective 
  persons 
  would 
  have 
  removed 
  the 
  source 
  from 
  which 
  the 
  flies 
  

   crowding 
  in 
  to 
  replace 
  those 
  caught 
  might 
  have 
  drawn 
  fresh 
  infection. 
  

  

  The 
  use 
  of 
  limed 
  screens. 
  — 
  This 
  method 
  was 
  also 
  considered, 
  and 
  Mr. 
  Ralph, 
  the 
  

   Public 
  Works 
  foreman 
  in 
  Mwanza, 
  made 
  me 
  an 
  excellent 
  revolving 
  screen 
  on 
  the 
  lines 
  

   long 
  ago 
  suggested 
  by 
  Dr. 
  Shircore 
  (Trans. 
  Soc. 
  Trop. 
  Med. 
  & 
  Hyg., 
  London, 
  ix, 
  

   Jan. 
  1916, 
  pp. 
  101-103). 
  Life-sized 
  silhouettes 
  of 
  men 
  were 
  painted 
  in 
  hartebeest 
  

   blood, 
  which 
  dried 
  brown, 
  on 
  each 
  of 
  the 
  four 
  vanes 
  (three 
  would 
  have 
  moved 
  better) 
  

   and 
  the 
  effect 
  as 
  these 
  turned 
  was 
  most 
  striking. 
  From 
  a 
  short 
  distance 
  and 
  partly 
  

   concealed 
  by 
  bush 
  it 
  looked 
  like 
  an 
  endless 
  succession 
  of 
  natives 
  turning 
  a 
  corner. 
  

   Mr. 
  Tully 
  and 
  I 
  caught 
  17 
  tsetses 
  off 
  it 
  in 
  about 
  20 
  minutes, 
  near 
  Zagayu, 
  but 
  the 
  

   impossibility 
  of 
  obtaining 
  good 
  bird-lime 
  prevented 
  its 
  proper 
  trial. 
  That 
  referred 
  

   to 
  took 
  place 
  in 
  a 
  spot 
  where 
  the 
  flies 
  were 
  not 
  at 
  the 
  moment 
  abundant 
  and, 
  while 
  

   it 
  is 
  possible 
  that 
  we 
  with 
  our 
  scent 
  assisted 
  to 
  attract 
  them, 
  they 
  went 
  to 
  the 
  screen 
  

   rather 
  than 
  to 
  ourselves. 
  I 
  tried 
  it 
  both 
  with 
  and 
  without 
  a 
  loin-rag, 
  freshly 
  removed 
  

   from 
  a 
  native 
  and 
  placed 
  on 
  it, 
  but 
  could 
  not 
  decide 
  that 
  it 
  made 
  a 
  difference. 
  The 
  

   dry 
  blood 
  attracted 
  house-flies 
  in 
  great 
  numbers, 
  but 
  the 
  tsetses 
  settled 
  as 
  freely 
  

   on 
  any 
  exposed 
  woodwork 
  ; 
  they 
  avoided 
  the 
  white 
  background. 
  The 
  screen 
  was 
  

   finally 
  smeared 
  with 
  indifferent 
  lime 
  and 
  set 
  up 
  on 
  Mugasiro 
  island, 
  but, 
  the 
  bird- 
  

   lime 
  having 
  dried 
  on 
  the 
  way 
  over, 
  caught 
  three 
  flies 
  only 
  (palpalis) 
  . 
  A 
  small 
  simple 
  

  

  