The Technique for Characterizing Mammalian Spermatozoa as Dead or Living by Differential Staining

A staining technique has been described which separates mammalian spermatozoa into two groups; viz., stained or dead cells and unstained or presumably live cells. The differential staining technique has been shown to be applicable to human, ram, bull, rabbit, and stallion spermatozoa. A substance present in the semen plasma of the boar interferes with the differential staining of the spermatozoa of this species. The water-soluble halogen derivatives of fluorescein were the only dyes studied capable of differentially staining mammalian spermatozoa. A new background stain, fast green FCF has been investigated and found superior to opal blue for this purpose. Studies with the staining principle have shown that differential staining is dependent upon the presence of ionizable substances and that the pH must be held within a narrow range for optimal staining results.