 action phytohaemagglutinin vitro lymphocyt chronic lymphoid leukaemia vitro action phytohaemagglutinin subject compar investig lymphocyt 13 normal subject 15 case chronic lymphat leukaemia group cellular chang appear larg basophil nucleol cell show mitot activ case lymphat leukaemia percentag cell undergo chang lower normal subject transform occur slowli phenomena strike higher initi leucocytosi chronic lymphat leukaemia cell transform residu normal lymphoid element leukaem lymphoid cell appear incap transform 