398 
Insects  and  Flowers. 
Am.  Jour.  Pharm. 
Aug.,  1886. 
reaction  with  sulphuric  acid  and  potassium  bichromate,  but  differing 
essentially  from  this  by  the  color  being  permanent. 
By  the  oxidation  of  colophony  with  dilute  nitric  acid  Schroder  ob- 
tained isophtalic,  trimellithic  and  terebinic  acids.  By  the  oxidation 
of  50  gms.  of  spruce  resin  with  nitric  acid  I  obtained  only  picric  acid. 
From  the  latter  the  potassium  and  sodium  salts  were  prepared  and 
obtained  in  handsome  crystals,  which  explode  like  gunpowder  when 
heated  on  platinum-foil. 
From  the  results  of  this  investigation  it  will  be  seen  that  the  so- 
called  spruce-gum  differs  in  many  respects  from  the  other  balsamic 
exudations  of  the  Coniferse,  which  have  as  yet  been  chemically  exam- 
ined.—  Contrib.  Dep.  Phar.,  Univ.  Wise,  1886,  pp.  30-34. 
INSECTS  AND  FLOWERS:  A  QUESTION.1 
By  C.  E.  Meetkeerke. 
Nearly  four  years  ago  a  paper  was  published  in  Chamber's  Journal? 
purporting  to  give  a  short  summary  of  the  discoveries  which  had 
been  made  up  to  that  time  by  a  great  many  careful  inquirers  on  the 
subject  of  insect  agency  in  the  fertilization  of  flowers.  Since  then 
the  Knight-Darwin  theory,  as  it  is  called  in  Germany,  has  progressed 
with  such  a  rush  in  one  direction  that  a  reaction  is  already  setting 
in,  and  it  is  now  almost  beginning  to  be  doubted,  not  only  if  cross- 
fertilization  is  necessary  to  the  life  of  plants,  but  even  if  it  is  par- 
ticularly advantageous  to  them. 
When  Sprengel,  Knight,  Delpino,  Miiller,  and  a  host  of  other 
writers,  asserted  that  the  aid  of  insects  was  necessary  for  the  com- 
plete fertility  of  plants,  and  when  Charles  Darwin  undertook  his 
own  practical  researches  on  the  subject,  little  doubt  was  left  upon 
the  minds  of  unprejudiced  people  as  to  the  intimate  relations  exist- 
ing between  the  animal  and  vegetable  kingdoms.  Darwin  was  sup- 
posed to  have  freed  himself  from  what  were  held  to  be  the  mistakes 
of  Sprengel  and  the  early  investigators,  but  even  he  had  ventured 
to  affirm  the  general  truth  of  their  conclusions  before  he  had  himself 
engaged  in  any  very  critical  researches.  Some  contradictions  arose, 
and  it  was  remarked  that  the  records  of  botanical  literature  are 
1  From  the  Medical  Bulletin,  May. 
2  Chambers'  Journal,  June,  1882. 
