﻿DESTRUCTIVE 
  DISTILLATION 
  OF 
  ANIMAL 
  SUBSTANCES. 
  249 
  

  

  has 
  been 
  made 
  in 
  the 
  first 
  part 
  of 
  this 
  paper. 
  As, 
  however, 
  I 
  observed 
  that 
  a 
  very 
  

   powerful 
  and 
  pungent 
  odour 
  was 
  evolved 
  when 
  the 
  fluid 
  began 
  to 
  boil, 
  and 
  the 
  

   vapours 
  presented 
  the 
  characteristic 
  reaction 
  of 
  pyrrol 
  in 
  a 
  very 
  high 
  degree, 
  the 
  

   head 
  of 
  the 
  boiler 
  was 
  luted 
  on, 
  and 
  the 
  condenser 
  attached, 
  for 
  the 
  purpose 
  of 
  

   endeavouring 
  to 
  obtain 
  that 
  substance, 
  which 
  in 
  my 
  previous 
  experiments 
  I 
  had 
  

   not 
  done. 
  The 
  fluid 
  which 
  distilled 
  over 
  carried 
  with 
  it 
  a 
  small 
  quantity 
  of 
  oil, 
  

   which, 
  at 
  the 
  moment 
  of 
  distillation, 
  was 
  perfectly 
  colourless, 
  but 
  soon 
  acquired 
  

   a 
  reddish 
  shade, 
  and 
  in 
  the 
  course 
  of 
  a 
  few 
  days 
  became 
  almost 
  black. 
  The 
  

   greater 
  part 
  of 
  this 
  oil 
  passed 
  over 
  with 
  the 
  first 
  portion 
  of 
  water 
  ; 
  but 
  the 
  last 
  

   traces 
  adhered 
  with 
  great 
  obstinacy 
  to 
  the 
  acid 
  fluid, 
  and 
  could 
  only 
  be 
  separated 
  

   by 
  very 
  protracted 
  distillation. 
  The 
  substance 
  thus 
  obtained 
  proved 
  to 
  be 
  a 
  

   mixture 
  of 
  an 
  oil 
  insoluble 
  in 
  acids, 
  and 
  which 
  appeared 
  to 
  be 
  merely 
  a 
  small 
  

   quantity 
  of 
  the 
  crude 
  oil, 
  mechanically 
  mixed 
  with 
  the 
  fluid, 
  and 
  of 
  a 
  series 
  of 
  

   bases 
  of 
  very 
  remarkable 
  properties, 
  and 
  obviously 
  related 
  to 
  one 
  another, 
  to 
  

   which 
  I 
  shall 
  afterwards 
  refer 
  under 
  the 
  provisional 
  name 
  of 
  pyrrol 
  bases. 
  

  

  When 
  these 
  substances 
  had 
  entirely 
  distilled, 
  the 
  fluid 
  was 
  allowed 
  to 
  cool, 
  

   excess 
  of 
  slaked 
  lime 
  added, 
  and 
  the 
  distillation 
  again 
  commenced, 
  in 
  order 
  to 
  

   obtain 
  the 
  bases 
  which 
  had 
  been 
  retained 
  by 
  the 
  sulphuric 
  acid. 
  The 
  separation 
  of 
  

   these 
  was 
  conducted 
  in 
  a 
  manner 
  in 
  all 
  respects 
  similar 
  to 
  that 
  employed 
  in 
  the 
  

   former 
  preparations, 
  solid 
  caustic 
  potash 
  being 
  added 
  in 
  sufficient 
  quantity 
  to 
  cause 
  

   the 
  separation 
  of 
  the 
  bases 
  held 
  in 
  solution 
  in 
  the 
  water. 
  The 
  potash 
  fluid, 
  however, 
  

   retained 
  a 
  certain 
  proportion 
  of 
  ammonia, 
  another 
  gaseous 
  base, 
  and 
  of 
  the 
  most 
  

   volatile 
  bases, 
  which 
  could 
  be 
  separated 
  only 
  by 
  a 
  very 
  large 
  excess 
  of 
  potash. 
  

   The 
  fluid 
  was 
  therefore 
  distilled 
  in 
  glass 
  vessels, 
  and 
  the 
  product 
  collected 
  in 
  a 
  

   succession 
  of 
  three 
  receivers, 
  the 
  first 
  of 
  which 
  was 
  kept 
  cold 
  by 
  water, 
  the 
  second 
  

   by 
  a 
  freezing 
  mixture, 
  and 
  the 
  third 
  contained 
  hydrochloric 
  acid, 
  for 
  the 
  purpose 
  

   of 
  condensing 
  the 
  gaseous 
  products. 
  The 
  first 
  receiver 
  now 
  contained 
  the 
  bases 
  

   dissolved 
  in 
  a 
  small 
  quantity 
  of 
  water, 
  from 
  which 
  they 
  were 
  readily 
  separated 
  

   by 
  potash 
  ; 
  the 
  second 
  receiver 
  contained 
  only 
  a 
  drop 
  or 
  two 
  of 
  liquid 
  ; 
  but 
  in 
  the 
  

   third 
  the 
  hydrochloric 
  acid 
  was 
  rapidly 
  saturated, 
  and 
  required 
  repeated 
  renewal 
  

   during 
  the 
  progress 
  of 
  the 
  distillation. 
  

  

  The 
  hydrochloric 
  solution 
  thus 
  obtained 
  contained 
  a 
  very 
  large 
  quantity 
  of 
  

   chloride 
  of 
  ammonium, 
  along 
  with 
  a 
  small 
  proportion 
  of 
  another 
  base, 
  in 
  order 
  to 
  

   obtain 
  which 
  the 
  fluid 
  was 
  slowly 
  evaporated, 
  allowed 
  to 
  cool 
  at 
  intervals, 
  and 
  

   the 
  sal-ammoniac 
  which 
  deposited 
  was 
  separated 
  by 
  straining 
  through 
  cloth 
  and 
  

   expression. 
  After 
  the 
  separation 
  of 
  several 
  crops 
  of 
  crystals, 
  a 
  dark-brown 
  

   mother 
  liquor 
  was 
  left, 
  which 
  refused 
  to 
  crystallize 
  by 
  evaporation 
  on 
  the 
  water- 
  

   bath, 
  but 
  on 
  cooling 
  solidified 
  into 
  a 
  mass 
  of 
  long 
  foliated 
  crystals, 
  which 
  soon 
  

   deliquesced 
  in 
  moist 
  air. 
  These 
  crystals 
  still 
  contained 
  traces 
  of 
  sal-ammoniac, 
  

   for 
  the 
  separation 
  of 
  which 
  they 
  were 
  evaporated 
  to 
  complete 
  dryness 
  on 
  the 
  

   water-bath, 
  and 
  dissolved 
  in 
  the 
  smallest 
  possible 
  quantity 
  of 
  absolute 
  alcohol, 
  

  

  