﻿368 
  LEONARD 
  ROGERS. 
  

  

  the 
  great 
  majority 
  of 
  cacliexial 
  fevers 
  with 
  enlarged 
  spleens 
  

   occurring 
  so 
  commonly 
  in 
  Calcutta, 
  and 
  also 
  in 
  still 
  larger 
  

   numbers 
  in 
  all 
  cases 
  of 
  active 
  kala-azar, 
  wliicli, 
  as 
  I 
  main- 
  

   tained 
  in 
  1897, 
  is 
  nothing 
  but 
  a 
  severe 
  form 
  of 
  the 
  disease 
  

   hitherto 
  known 
  as 
  " 
  malarial 
  cachexia/' 
  but 
  for 
  which 
  I 
  have 
  

   suggested 
  the 
  more 
  appropriate 
  one 
  of 
  ^'cacliexial 
  fever" 
  

   until 
  further 
  advances 
  in 
  our 
  knowledge 
  of 
  the 
  new 
  parasite 
  

   enabled 
  a 
  better 
  one 
  to 
  be 
  decided 
  on. 
  In 
  the 
  course 
  of 
  my 
  

   recent 
  investigations 
  I 
  tried 
  various 
  methods 
  of 
  studying 
  the 
  

   parasites 
  outside 
  the 
  body, 
  and 
  eventually 
  found 
  one 
  by 
  

   which 
  they 
  could 
  be 
  kept 
  alive 
  for 
  some 
  days, 
  during 
  which 
  

   they 
  multiplied 
  greatly, 
  and 
  in 
  some 
  instances 
  developed 
  new 
  

   forms 
  of 
  considerable 
  interest. 
  The 
  method 
  by 
  means 
  of 
  

   which 
  these 
  results 
  have 
  been 
  obtained 
  is 
  an 
  extremely 
  simple 
  

   one. 
  The 
  blood 
  obtained 
  by 
  spleen 
  puncture 
  was 
  imme- 
  

   diately 
  ejected 
  into 
  small 
  sterile 
  test-tubes 
  containing 
  a 
  little 
  

   sodium 
  citrate 
  to 
  prevent 
  the 
  blood 
  from 
  coagulating, 
  and 
  

   these 
  were 
  then 
  incubated 
  at 
  varying 
  temperatures, 
  portions 
  

   of 
  the 
  culture 
  being 
  removed 
  with 
  a 
  platinum 
  loop 
  from 
  time 
  

   to 
  time 
  for 
  examination 
  with 
  the 
  microscope. 
  At 
  blood 
  heat 
  I 
  

   found 
  the 
  spleen 
  parasites 
  rapidly 
  underwent 
  degenerative 
  

   changes, 
  and 
  after 
  twenty-four 
  hours 
  most 
  of 
  them 
  had 
  disap- 
  

   peared 
  and 
  the 
  remainder 
  stained 
  badly. 
  As 
  the 
  presence 
  of 
  

   a 
  macro- 
  and 
  a 
  micro-nucleus 
  in 
  the 
  spleen 
  parasites 
  pointed 
  to 
  

   their 
  possible 
  relationship 
  with 
  the 
  flagellated 
  class 
  of 
  proto- 
  

   zoa, 
  and 
  it 
  is 
  known 
  that 
  trypanosomes 
  live 
  much 
  longer 
  out 
  

   of 
  the 
  body 
  at 
  low 
  temperatures 
  than 
  at 
  blood 
  heat, 
  I 
  next 
  

   tried 
  incubating 
  the 
  culture 
  tubes 
  in 
  a 
  cold 
  incubator 
  at 
  27° 
  

   C, 
  ice 
  being 
  used, 
  as 
  the 
  laboratory 
  temperature 
  was 
  several 
  

   degrees 
  above 
  that 
  point. 
  At 
  this 
  temperature 
  I 
  found 
  that 
  

   the 
  parasites 
  lived 
  for 
  some 
  days, 
  retaining 
  fully 
  their 
  stain- 
  

   ing 
  properties. 
  Further, 
  in 
  favourable 
  cases, 
  in 
  which 
  a 
  

   large 
  number 
  of 
  parasites 
  were 
  present 
  in 
  the 
  blood 
  when 
  

   first 
  obtained 
  (which 
  is 
  only 
  the 
  case 
  in 
  about 
  one 
  fifth 
  of 
  

   those 
  met 
  with 
  in 
  Calcutta), 
  it 
  was 
  soon 
  evident 
  that 
  they 
  

   were 
  undergoing 
  division 
  and 
  increasing 
  very 
  materially 
  in 
  

   numbers, 
  for, 
  instead 
  of 
  two 
  or 
  three 
  in 
  a 
  field 
  of 
  an 
  immer- 
  

  

  