Dear Histoneteers, Can someone please explain to me why some tissue fixation protocols call for 4% paraformaldehyde while others call for 10% formaldehyde and what the difference is? Thanks, Sharon -- Sharon Cooperman <scoop <@t> mail.nih.gov> NIH, NICHD, CBMB 301.435-7735 Building 18T, room 101 301.402-0078 fax Bethesda, MD 20892