﻿210 
  

  

  Prof. 
  B. 
  Moore 
  and 
  Mr. 
  T. 
  A. 
  Webster. 
  

  

  The 
  small 
  growth 
  in 
  No. 
  8 
  with 
  lid 
  screwed 
  down 
  shows 
  that 
  available 
  

   phosphates 
  and 
  sources 
  of 
  nitrogen 
  may 
  be 
  present, 
  but 
  when 
  the 
  supply 
  of 
  

   carbon 
  dioxide 
  is 
  cut 
  off, 
  and 
  no 
  substitute 
  supplied, 
  no 
  photo-synthesis 
  can 
  

   occur. 
  This 
  is 
  obvious, 
  but 
  No. 
  8 
  is 
  a 
  necessary 
  control 
  to 
  No. 
  7 
  where 
  

   C0 
  2 
  is 
  supplied 
  from 
  the 
  air, 
  and 
  to 
  Nos. 
  9 
  and 
  11, 
  where 
  the 
  air 
  is 
  shut 
  out, 
  

   but 
  a 
  supply 
  of 
  excessively 
  dilute 
  vapours 
  of 
  formaldehyde 
  and 
  methylic 
  

   alcohol 
  respectively 
  are 
  obtained 
  from 
  these 
  substances 
  contained 
  in 
  narrow 
  

   test-tubes 
  placed 
  slantingly 
  in 
  the 
  jars 
  before 
  the 
  lids 
  were 
  screwed 
  down. 
  

   The 
  result 
  demonstrates 
  that 
  supplied 
  in 
  this 
  manner 
  the 
  vapours 
  of 
  these 
  

   simple 
  organic 
  substances 
  can 
  substitute 
  carbon 
  dioxide 
  quite 
  well, 
  there 
  

   being 
  3'8 
  mgrm. 
  of 
  nitrogen 
  with 
  the 
  formaldehyde 
  vapour 
  and 
  7*4 
  mgrm. 
  

   with 
  the 
  methylic 
  alcohol, 
  as 
  against 
  07 
  mgrm. 
  in 
  the 
  control. 
  This 
  does 
  

   not 
  show 
  quantitatively 
  that 
  methylic 
  alcohol 
  is 
  better 
  as 
  a 
  nutrient 
  than 
  

   formaldehyde, 
  for 
  with 
  somewhat 
  increased 
  concentrations 
  both 
  vapours 
  would 
  

   kill 
  the 
  growing 
  green 
  cells, 
  and 
  it 
  is 
  a 
  difficult 
  problem 
  so 
  to 
  regulate 
  the 
  

   concentration 
  of 
  each 
  at 
  these 
  excessive 
  dilutions 
  that 
  the 
  maximum 
  

   beneficial 
  result 
  is 
  obtained. 
  The 
  real 
  point 
  is 
  that 
  these 
  vapours 
  of 
  simple 
  

   organic 
  substances, 
  when 
  sufficiently 
  dilute, 
  act 
  not 
  as 
  poisons 
  to 
  the 
  green 
  

   cell 
  but 
  as 
  nutrients 
  which 
  can 
  replace 
  carbon 
  dioxide. 
  

  

  The 
  bearing 
  of 
  these 
  results 
  upon 
  the 
  fundamental 
  hypothesis 
  of 
  Baeyer, 
  

   that 
  the 
  first 
  step 
  in 
  the 
  synthesis 
  in 
  green 
  cells, 
  of 
  the 
  organic 
  from 
  the 
  

   inorganic, 
  is 
  formaldehyde, 
  is 
  so 
  intimate 
  that 
  a 
  little 
  more 
  consideration 
  

   appears 
  desirable. 
  Hitherto 
  this 
  hypothesis 
  has 
  rested 
  mainly 
  upon 
  cir- 
  

   cumstantial 
  evidence. 
  No 
  one 
  has 
  ever 
  been 
  able 
  to 
  demonstrate 
  the 
  

   presence 
  of 
  formaldehyde 
  in 
  the 
  living 
  cell. 
  Various 
  solutions 
  of 
  chlorophyll 
  

   and 
  emulsions 
  of 
  chlorophyll 
  in 
  water, 
  or 
  upon 
  colloidal 
  membranes, 
  such 
  

   as 
  gelatine, 
  have 
  been 
  exposed 
  to 
  light, 
  and 
  afterwards 
  formaldehyde 
  has 
  been 
  

   tested 
  for 
  by 
  delicate 
  chemical 
  tests. 
  The 
  results 
  have 
  been 
  contradictory 
  ; 
  

   some 
  observers 
  have 
  found 
  formaldehyde 
  and 
  others 
  have 
  failed 
  to 
  detect 
  it. 
  

   But 
  we 
  have 
  previously 
  shown 
  that 
  practically 
  any 
  organic 
  system, 
  when 
  

   exposed 
  to 
  light, 
  yields 
  formaldehyde. 
  Hence 
  the 
  presence 
  of 
  formaldehyde 
  

   under 
  such 
  conditions 
  means 
  nothing 
  and 
  probably 
  comes 
  from 
  a 
  reversed 
  

   system, 
  not 
  of 
  building 
  up 
  but 
  of 
  breaking 
  down 
  of 
  organic 
  substances. 
  

   Even 
  if 
  formaldehyde 
  could 
  be 
  shown 
  intra-vitally 
  in 
  a 
  living 
  cell 
  it 
  might 
  

   only 
  mean 
  excessive 
  light 
  exposure 
  and 
  breaking 
  down 
  of 
  living 
  substance 
  

   and 
  not 
  building 
  up. 
  We 
  have 
  pointed 
  out 
  the 
  same 
  in 
  previous 
  com- 
  

   munications 
  (3, 
  etc.), 
  viz., 
  that 
  the 
  lethal 
  action 
  of 
  light 
  upon 
  bacteria 
  and 
  

   other 
  living 
  cells 
  is 
  probably 
  due 
  to 
  such 
  a 
  reversed 
  reaction, 
  in 
  which 
  

   formaldehyde 
  and 
  other 
  simple 
  and 
  poisonous 
  organic 
  substances 
  are 
  set 
  free. 
  

  

  The 
  other 
  channel 
  of 
  approach 
  experimentally 
  to 
  this 
  question 
  is 
  more 
  

  

  