<cri_photo_page comet_assay4 | stock_photo:labs:envi_tox:activities:comet_assay:comet_assay4_s.jpg | stock_photo:labs:envi_tox:activities:comet_assay:comet_assay4_l.jpg | stock_photo:labs:envi_tox:activities:comet_assay:comet_assay4_o.jpg | 27 January 2009 | Comet assay >