Amount  of  guinea-pig  serum  (complement)  added  to  the  standardised  haemolytic  system,  consisting  of  o’oo2  c.c. 
amboceptor  and  i  c.c.  of  a  5  %  suspension  of  red  cells.  In  each  case  the  contents  of  the  tubes  were  made  up 
to  3  c.c.  with  0-9  %  NaCl  solution. 
