﻿MacDougal: 
  Growth 
  of 
  the 
  tomato 
  2G5 
  

  

  \ 
  

  

  plasmatic 
  mass 
  to 
  realize 
  that 
  the 
  albumin 
  and 
  mucilage 
  may 
  be 
  

   taken 
  to 
  be 
  in 
  an 
  interwoven 
  meshwork, 
  or 
  if 
  in 
  suspension 
  in 
  

   separate 
  globules. 
  ^ 
  - 
  ' 
  

  

  i 
  

  

  This 
  being 
  the 
  case, 
  one 
  may 
  take 
  up 
  water 
  and 
  swell, 
  or 
  lose 
  

   water 
  and 
  shrink, 
  while 
  the 
  reverse 
  action 
  takes 
  place 
  in 
  the 
  other, 
  

   which 
  might 
  also 
  remain 
  inactive. 
  Thus 
  the 
  albumins 
  swell 
  most 
  

   in 
  acids 
  or 
  under 
  the 
  influence 
  of 
  free 
  hydrogen 
  ions, 
  although 
  

   being 
  amphoteric 
  they 
  may 
  also 
  swefl 
  in 
  hydroxyl 
  ions 
  or 
  under 
  

   the 
  action 
  of 
  bases, 
  while 
  they 
  are 
  not 
  very 
  active 
  in 
  solutions 
  of 
  

   amino-compounds. 
  The 
  mucilages 
  on 
  the 
  other 
  hand 
  are 
  weak 
  

   acids, 
  swelling 
  but 
  little 
  in 
  acids, 
  more 
  under 
  the 
  action 
  of 
  hydroxyl 
  

   ions 
  or 
  bases, 
  still 
  more 
  in 
  water, 
  and 
  reaching 
  a 
  maximum 
  in 
  

   amino-compounds. 
  

  

  Mixtures 
  of 
  mucilages 
  and 
  of 
  albumins 
  will, 
  in 
  the 
  main, 
  show 
  

   reactions 
  determined 
  by 
  the 
  element 
  which 
  makes 
  up 
  the 
  largest 
  

   proportion 
  of 
  its 
  mass. 
  It 
  follows 
  therefore 
  that 
  the 
  growing 
  

   cell-masses 
  of 
  plants 
  show 
  swelling, 
  hydration 
  and 
  growth 
  reactions 
  

   determined 
  by 
  the 
  mucilages 
  or 
  pentosans, 
  as 
  modified 
  by 
  the 
  

   albumins, 
  acids, 
  and 
  salts 
  present. 
  

  

  F 
  

  

  When 
  we 
  take 
  up 
  the 
  facts 
  disclosed 
  by 
  chemical 
  analyses 
  of 
  

   tomatoes, 
  we 
  discover 
  five 
  things 
  which 
  must 
  be 
  taken 
  into 
  account 
  

   m 
  any 
  attempt 
  to 
  make 
  a 
  physical-chemical 
  explanation 
  of 
  growth 
  

   These 
  are 
  as 
  follows: 
  (i) 
  the 
  proportion 
  of 
  sugar, 
  including 
  the 
  

   mucilages, 
  in 
  the 
  dry 
  material 
  increases 
  from 
  9 
  to 
  37 
  per 
  cent 
  in 
  

   the 
  stage 
  of 
  enlargement 
  including 
  the 
  formation 
  of 
  the 
  seeds; 
  

   (2) 
  the 
  acids, 
  which 
  include 
  malic, 
  phosphoric 
  and 
  citric, 
  increase 
  

   toward 
  maturity; 
  (3) 
  the 
  albumins 
  decrease 
  with 
  development; 
  

   (4) 
  the 
  ash 
  or 
  metallic 
  bases 
  increase 
  from 
  4.5 
  to 
  10.75 
  P^^ 
  ^^^t 
  of 
  

   the 
  dry 
  weight; 
  and 
  (5) 
  the 
  proportion 
  of 
  cellulose 
  lessens 
  as 
  the 
  

   fruit 
  proceeds 
  toward 
  maturity. 
  

  

  If 
  due 
  weight 
  be 
  given 
  to 
  these 
  factors 
  or 
  agencies 
  the 
  procedure 
  

   in 
  growth 
  may 
  be 
  determined. 
  Thus 
  in 
  the 
  earlier 
  stages 
  the 
  

   total 
  albumins 
  constitute 
  less 
  than 
  3 
  per 
  cent 
  of 
  the 
  dry 
  weight 
  

   and 
  the 
  sugars 
  over 
  10 
  per 
  cent, 
  of 
  which 
  at 
  least 
  one 
  third 
  may 
  be 
  

  

  F 
  

  

  taken 
  to 
  be 
  pentosans 
  or 
  mucilages. 
  The 
  colloidal 
  mixture 
  of 
  

   equal 
  parts 
  of 
  the 
  two 
  — 
  mucilages 
  and 
  albumins 
  — 
  might 
  be 
  

   capable 
  of 
  showing 
  a 
  hydration 
  capacity 
  of 
  over 
  3,000 
  per 
  cent 
  in 
  a 
  

   cell 
  sap 
  containing 
  any 
  one 
  of 
  a 
  number 
  of 
  amino-acids 
  which 
  are 
  

  

  