New High-efficiency Light Source for Immunofluorescence Microscopy

THE light source usually employed in fluorescence microscopy is a high-pressure mercury vapour lamp; when Coon's antibody technique is used, this source has some disadvantages. The maximum absorption band of the fluorescein isothiocyanate which lies approximately between 440 and 510 nm (the continuous curve in Fig. 1) does not overlap with the mercury emission lines at 365, 405 and 435 nm used for exciting the fluorescence. Another inconvenience arises from the fact that there are two strong mercury lines (546 and 577 nm) in the fluorescence spectrum (the dotted curve in Fig. 1). This latter inconvenience is partially removed by the use of adecvated fluorescence and suppression filters.