AmjJne?i9i5arm'}  Effect  uPon  Acidity  of  Tomato  Fruits.  279 
or  those  ripened  at  the  temperature  of  the  laboratory.  (3)  There 
are  considerable  differences  in  the  acidity  of  varieties,  but,  judging 
from  the  results  of  these  tests,  the  normally  ripened  fruits  of  yellow 
varieties  commonly  contain  as  much  acid  as  those  of  red  varieties. 
The  several  facts  brought  out  by  these  tests  render  it  obvious  that 
there  is  now  not  sufficient  evidence  to  justify  relating  pigmentation 
to  total  acidity.  The  acidity  changes  are,  however,  interesting  in 
themselves,  in  these  as  well  as  in  other  fruits.  No  attempt  was  made 
to  follow  progressively  any  changes  in  acidity  induced  by  condi- 
tions ;  but  in  titrating  on  one  occasion,  after  an  interval  of  two  days, 
new  samples  of  both  red  and  yellow  fruits  which  had  been  ripened 
in  the  laboratory,  it  was  found  that  the  acidity  had  noticeably  de- 
clined since  the  previous  titrations  from  the  same  lots  of  fruits. 
We  have  reckoned  the  acidity  of  the  tomato  in  terms  of  citric 
acid,  as  is  customary.  It  should  be  noted,  however,  that,  while 
Bowman3  and  others  report  citric  as  the  chief  acid  of  the  tomato, 
Albahary,1  on  the  contrary,  gives  0.48  per  cent,  as  the  malic  acid 
content  and  0.09  per  cent,  as  that  of  citric  acid  in  the  fresh  fruits. 
The  author  last  mentioned  gives  no  indications  respecting  the  variety 
or  condition  of  the  fruit  employed.  In  a  later  contribution2  he  re- 
ports the  results  of  analyzing  tomato  fruits  in  different  stages  of 
maturation,  as  follows:  "i°  le  fruit  vert  avant  l'apparition  de  la 
graine  dans  la  pulpe;  2°  le  fruit  vert  au  moment  ou  la  graine  est 
completement  formee;  30  le  fruit  rouge  arrive  a  sa  pleine  matura- 
tion." In  the  second  stage,  corresponding  to  practically  full-grown, 
green,  he  finds  0.58,  and  in  the  ripe  fruits  0.42  per  cent.,  of  organic 
acids.  This  is  in  complete  agreement  with  our  findings.  In  the 
earliest  stage  of  fruit  development  Albahary  finds  an  acid  content 
of  only  0.1 16  per  cent.  Wehmer,5  after  quoting  Albahary1  as  to  the 
percentage  of  the  various  acids  in  the  fruit,  remarks,  "  Die  Aciditat 
wechselt  stark  je  nach  dem  Reifestadium  (von  0.06-0.697  per  cent, 
des  Saftes  auf  Citronensaure  berechnet)."  He  does  not  indicate 
the  source  of  these  data,  and  certainly  the  smaller  percentage  given 
can  refer  only  to  the  youngest  stages  of  fruit  development. 
Graduate  Laboratory,  Missouri  Botanical  Garden. 
Literature  Consulted. 
1  Albahary,  J.  M. :  Analyse  complete  du  fruit  du  Lycopersicum  esculentum  ou 
Tomate.    Compt.  rend.  acad.  Paris  145 :  131-133.  1907. 
2  ,  Etude  chimique  de  la  maturation  du  Lycopersicum  esculentum 
(Tomate).    Compt.  rend.  acad.  Paris  147:  146-147.  1908. 
