48  Recent  Researches  in  Botany.  {^"^'j^n^'S^r^^- 
the  base  of  the  ovary,  Professor  Huxley  pointed  out  the  lines  along  which 
the  probable  evolution  of  the  Gentianacese  have  taken  place,  and  also- 
sketched  a  hypothetical  ancestor. 
It  is  interesting  to  note  that  this  arrangement,  which  I  think  I  may  call  a 
biological  arrangement,  differs  materially  from  the  ordinary  arrangement, 
such  as  given,  for  instance,  in  Hooker  and  Bentham's  "  Genera  Planta- 
rum." 
Passing  now  from  a  consideration  of  the  structure  of  the  "  gentians,"  I 
would  turn  your  attention  to  a  certain  abnormal  phenomenon  in  the  life 
history  of  a  fern  known  as  "  apospory,"  whereby  the  usual  life  cycle  is 
shortened.  Professor  Bower  has  shown  that  in  the  case  of  Athyrium  Filix- 
fcemina  var.  darissima,  Jones,  complete  sporal  arrest  occasionally  takes 
place;  the  sporangia  instead  of  developing  spores  develop  into  prothalli. 
In  Polystichum  angidare  var.  pulcherrimum,  Padley,  this  phenomenon  also 
takes  place,  and,  furthermore,  prothalli  have  been  observed  to  develop  from 
points  on  the  frond  away  from  the  sori — in  this  case,  then,  the  sporangium 
is  also  eliminated. 
The  phenomenon  of  apospory  may  be  considered  as  a  mere  sport,  but 
certainly  a  peculiar  one,  interfering,  as  it  does,  to  such  a  large  extent  in  the 
life  history  of  the  plant  concerned. 
A  good  deal  of  attention  has  lately  been  paid  to  the  effect  various  chemi- 
cals have  in  stimulating  and  retarding  growth  in  plant  life. 
At  the  recent  meeting  of  the  British  Association  in  Manchester,  Dr.  Vines 
mentioned  some  experiments  he  had  been  making  with  the  two  alkaloids,, 
atropine  and  physostigmine.  Everybody  here  doubtless  is  acquainted  with 
the  action  of  these  two  bodies  when  used  in  eye  operations,  the  one  dilating 
the  pupil  of  the  eye,  and  the  other  causing  contraction.  They  possess  very 
marked  properties — the  one  being  exactly  antagonistic  to  the  other,  so  are 
well  suited  for  experiraentizing  with.  Their  action  was  tried  on  the  com- 
mon sensitive  plant  {Mimosa  pudica) ,  and  it  is  interesting  to  note  that,  as  in 
the  case  of  animal  tissues,  the  result  obtained  was  stimulation  of  the  vege- 
table cell  in  the  one  case,  and  contraction  in  the  other. 
This  effect  of  stimulating  vegetable  growth  has  been  the  subject  of  a  series 
of  experiments  conducted  at  Cambridge  by  Anna  Bateson  and  Francis  Dar- 
win. If  the  turgescent  pith  from  a  growing  shoot  is  freed  from  the  external 
tissues,  it  exhibits  a  sudden  increase  in  length.  It  also  exhibits  increase  in 
length  if  placed  in  damp  air  or  water. 
This  latter  fact,  and  the  possibility  of  accelerating  and  retarding  the  rate 
of  increase  in  length  by  various  reagents,  was  made  the  point  of  a  number 
of  careful  observations. 
The  pith,  obtained  either  from  the  Jerusalem  artichoke  {Helianthus  tube- 
rosus)  or  sunflower  (H.  annum),  was  attached  to  the  bottom  of  a  narrow 
glass  jar,  the  upper  end  being  connected  by  means  of  a  thread  of  plaited  silk 
with  the  short  arm  of  an  auxanometer-lever  in  order  that  any  increase  in 
length  might  be  accurately  measured. 
If  a  strip  of  pith  is  filled  up  as  here  described  and  the  jar  is  then  filled 
with  water,  the  elongation  as  exhibited  by  the  descent  of  the  long  arm  of 
