﻿440 
  Branner 
  — 
  Bacteria 
  and 
  the 
  Decomposition 
  of' 
  Rocks. 
  

  

  nitrogen 
  in 
  some 
  available 
  form. 
  Frankland 
  used 
  a 
  solution 
  of 
  

   ammonium 
  chloride, 
  potassium 
  phosphate, 
  magnesium 
  sulphate, 
  

   calcium 
  chloride 
  and 
  calcium 
  carbonate.* 
  Here 
  the 
  carbon 
  

   was 
  supplied 
  by 
  the 
  calcium 
  carbonate 
  and 
  the 
  nitrogen 
  by 
  the 
  

   ammonium 
  chloride 
  (NH 
  4 
  C1). 
  Winogradsky 
  used 
  ammonium 
  

   carbonate, 
  from 
  which 
  both 
  nitrogen 
  and 
  carbon 
  could 
  be 
  

   derived. 
  

  

  It 
  is 
  safe 
  to 
  assume, 
  without 
  demonstration, 
  that 
  some 
  such 
  

   source 
  of 
  supply 
  of 
  these 
  two 
  substances 
  must 
  always 
  be 
  at 
  

   hand 
  or 
  else 
  these 
  organisms 
  cannot 
  live. 
  

  

  Leaving 
  aside 
  the 
  carbon, 
  the 
  only 
  known 
  mineral 
  sources 
  

   from 
  which 
  nitrogen 
  could 
  be 
  derived 
  are 
  the 
  nitrates 
  and 
  

   nitrites 
  and 
  a 
  few 
  others, 
  such 
  as 
  teschemacherite, 
  (acid 
  ammo- 
  

   nium 
  carbonate 
  (HNH 
  4 
  CO 
  s 
  ) 
  ), 
  from 
  guano 
  deposits, 
  and 
  sal- 
  

   ammoniac 
  (ammonium 
  chloride 
  (NH 
  4 
  C1)), 
  which 
  occurs 
  about 
  

   volcanoes.f 
  But 
  while 
  these 
  minerals 
  all 
  occur 
  in 
  nature, 
  

   sometimes 
  in 
  great 
  quantities, 
  as 
  in 
  the 
  great 
  niter 
  beds 
  of 
  the 
  

   world, 
  % 
  so 
  far 
  as 
  known, 
  they 
  are 
  all 
  produced 
  by 
  organic 
  

   agencies, 
  and 
  can 
  scarcely 
  be 
  regarded 
  as 
  what 
  geologists 
  know 
  

   as 
  " 
  rock-forming 
  minerals," 
  that 
  is, 
  minerals 
  that 
  enter 
  into 
  

   the 
  composition 
  of 
  crystalline, 
  eruptive, 
  metamorphic 
  or 
  wide- 
  

   spread 
  sedimentary 
  rocks. 
  It 
  is 
  true 
  that 
  these 
  minerals 
  may 
  

   be 
  carried 
  into 
  the 
  soil 
  and 
  into 
  the 
  rocks 
  by 
  infiltration, 
  and 
  

   Mrs. 
  Frankland 
  points 
  out 
  that 
  some 
  forms 
  thrive 
  in 
  carbon- 
  

   ated 
  waters.§ 
  But 
  even 
  then 
  bacteria 
  carried 
  in 
  with 
  such 
  

   waters 
  could 
  not 
  attack 
  the 
  rock-making 
  minerals 
  directly, 
  but 
  

   only 
  by 
  the 
  formation 
  of 
  organic 
  acids 
  by 
  their 
  own 
  decay. 
  

   But 
  this 
  simply 
  puts 
  them 
  back 
  in 
  the 
  position 
  of 
  other 
  forms 
  

   of 
  life 
  which 
  yield 
  organic 
  acids 
  upon 
  decomposing. 
  

  

  Attention 
  is 
  also 
  called 
  to 
  the 
  statement 
  of 
  Storer|j 
  that 
  

   Warington, 
  who 
  found 
  " 
  nitric 
  ferment 
  in 
  loam 
  at 
  various 
  

   depths, 
  was 
  no 
  longer 
  able 
  to 
  detect 
  it 
  with 
  constancy 
  and 
  cer- 
  

   tainty 
  at 
  depths 
  greater 
  than 
  36 
  inches 
  .... 
  In 
  none 
  of 
  his 
  

   experiments 
  was 
  nitrification 
  excited 
  by 
  soils 
  taken 
  from 
  

   depths 
  of 
  seven 
  and 
  eight 
  feet." 
  

  

  Again 
  he 
  says 
  " 
  In 
  order 
  that 
  nitrates 
  may 
  form 
  in 
  the 
  soil 
  

   there 
  must 
  be 
  free 
  access 
  of 
  air, 
  as 
  well 
  as 
  a 
  certain 
  amount 
  of 
  

   humidity 
  and 
  warmth." 
  

  

  * 
  Micro-organisms 
  in 
  their 
  relation 
  to 
  chemical 
  change, 
  by 
  Percy 
  F. 
  Frankland. 
  

   Nature, 
  xlvi, 
  1892, 
  136-138. 
  

  

  f¥. 
  L. 
  Watts 
  in 
  his 
  "Across 
  the 
  Yatn 
  a 
  Jokul," 
  pp. 
  110, 
  154, 
  mentions 
  con- 
  

   siderable 
  deposits 
  of 
  this 
  mineral 
  about 
  volcanoes. 
  Mr. 
  Watts 
  tells 
  me, 
  how- 
  

   ever, 
  that 
  he 
  doubts 
  the 
  correctness 
  of 
  the 
  determination. 
  

  

  ^Stutzer 
  and 
  Burri 
  are 
  said 
  to 
  have 
  found 
  bacteria 
  feeding 
  on 
  saltpeter: 
  

   Deutsch. 
  Landw. 
  Presse, 
  1894, 
  xxi, 
  No. 
  63, 
  p. 
  610. 
  

  

  § 
  Bacteria 
  and 
  carbonated 
  water, 
  by 
  G. 
  C. 
  Frankland. 
  Nature, 
  August 
  20, 
  1896, 
  

   375-376. 
  

  

  I 
  Agriculture 
  in 
  some 
  of 
  its 
  relations 
  with 
  chemistry, 
  by 
  F. 
  H. 
  Storer, 
  i, 
  299 
  

   and 
  305, 
  N. 
  Y., 
  1892. 
  

  

  