The  value  and  necessity  of  experimentation  wa.s  duly  recognized  by
Dr.  Yocom,  who  has  already  added  several  experiments  of  another
sort  to  this  essential  phase  of  the  problem.  "In  studying  Euplotes
patella"  (Yocom,  1918,  p.  363)  "that  have  been  treated  with  very
weak  solutions  of  certain  ahemicals,  such  as  neutral  red.  methylene
blue  and  especially  nicotine,  it  ha.s  been  noticed  that  the  anal  cirri  and
cytostomal  membranellcs  are  the  last  to  cease  moving.  The  other
cirri  become  quiet  but  the  membranelles  and  anal  cirri  have  been
seen  to  move  even  after  the  cytoplasm  lias  begun  to  break  up.  Such
phenomena  favor  very  strongly  the  idea  that  the  motorium  .serves  as
a  coordinating  center  between  the  anal  cirri  and  the  cytostomal  mem-
branelles. However,  other  observations  on  living  animals  give  even
stronger  evidence  in  favor  of  the  neural  function.  It  has  also  been
noted  in  specimens  subjected  to  a  very  weak  solution  of  nicotine  that
the  frontal,  ventral  and  marginal  cirri  continue  moving  even  after  the
animal  has  ceased  to  swim  about.  The  membranelles  also  move  but
more  slowly  than  in  normal  animals.  Occasionally  one  or  more  of  the
anal  cirri  may  be  seen  to  make  a  feeble  movement  not  sufficiently
strong  to  cause  the  animal  to  move.  However,  as  the  animal  revives
from  the  effects  of  the  narcotic  and  begins  to  swim  about  by  vigorous
kicks  of  the  anal  cirri,  a  decided  increase,  in  the  rate  of  movement  of
the  membranelles  may  be  noticed."


ACKNOWLEDGMENTS

This  experimental  investigation  has  been  made  under  the  very
helpful  direction  of  Professor  Charles  A.  Kofoid,  whose  kindly  and
stimulating  criticisms  have  contributed  much  to  any  merits  the  results
may  possess.
My  thanks  are  also  due  to  Professor  S.  S.  Maxwell  for  several
valuable  suggestions  on  methods  and  useful  literature.
