3.  We  have  already  referred  to  the  connection
between  the  lack  of  oxygen  and  the  onset  of  autolysis
and  disintegration  of  tissues  in  the  body.  It  is  of
interest  that  there  are  cells  in  which  the  disintegration
under  the  influence  of  lack  of  oxygen  is  so  rapid  that
it  can  be  followed  under  the  microscope.  The  writer
has  observed  that  certain  cells  undergo  complete  irre-
versible dissolution  in  a  very  short  time  under  the
influence  of  lack  of  oxygen,  e.  g.,  the  first  segmentation
cells  of  the  egg  of  a  teleost  fish  Ctenolahnis.^

»  Loeb,  J.,  Arch.  f.  d.  ges.  Physiol.,  1895,  Ixii.,  249.
35^  Death  and  Dissolution  of  the  Organism

When  these  eggs  are  deprived  of  oxygen  at  the  time  they
reach  the  eight-  or  sixteen-cell  stage,  it  can  be  noticed  that
the  membranes  of  the  blastomeres  are  transformed  into
small  droplets  within  half  an  hour  or  more,  according  to
the  temperature.  These  droplets  begin  to  flow  together,
forming  larger  drops.     [Figures  48  to  51  show  the  successive


Fig.  48


Fig.  49


4  ^/e\*


Fig.  51


stages  of  this  process.]  When  the  eggs  are  exposed  to  the
air  in  time,  segmentation  can  begin  again;  but  if  a  slightly
longer  time  is  allowed  to  elapse,  the  process  becomes  irre-
versible and  life  becomes  extinct.  Such  clear  structural
changes  cannot  often  be  observed  in  the  eggs  of  other
animals  under  the  same  conditions.  Are  these  chanees  of
structure  (apparently  liquefaction  of  solid  elements)  respon-
sible for  death  under  such  conditions?  In  order  to  obtain
an  answer  to  this  question,  the  writer  investigated  the


Death  and  Dissolution  of  the  Organism  357

eflect  of  the  lack  of  oxygen  upon  the  heart-beat  of  the  em-
bryo of  the  same  fish  Ctenolahrus.  This  egg  is  perfectly
transparent  and  the  heart-beat  can  easily  be  watched.
