Monochromatic Light Absorption by Normal Chicken Erythrocytes.
-J, 0. ELY AND M. H. Ross. The relative absorption of different wave lengths of monochromatic light by the nuclei of chicken erythrocytes was determined with equipment and technic similar to that used by Allen, Franklin and McDonald (I). The maximum absorption by the nuclei of the various wave lengths used was found to be at 2804 A. This differs somewhat from the maximum nuclear absorption of tumor nuclei found by the above-mentioned investigators, who found a maximum absorption at 2500 to 2600 a for a rat sarcoma. Gates (2) found that a maximum absorption of monochromatic light by StephyZococcus aureus and Escherichia coli was between 2600 and 2700 A. Weinstein (3) found that the maximum killing effect on paramecia of different wave lengths of monochromatic light was at 2800 A. The killing effect may be assumed to be correlated with maximum absorption since they occur at the same wave length: it appears, therefore, that the maximum absorption of the nuclei of different kinds of cells may be at different wave lengths.
The methods used in these studies were as follows. Thin coverglass smears of whole chicken blood were made on quartz cover-glasses. The smears were air-dried, then immersed in 95 per cent. ethyl alcohol for approximately 5 seconds, and then mounted on quartz slides with glycerol of 1.455 refractive index as the mounting medium. The edges of the preparation were then sealed with paraffin.
Photomicrographs were taken of a suitable microscopic field using an all-quartz optical system microcsope. Eastman Kodak Company Panatomic-X 35 mm. film was used and developed in Eastman Kodak Company developer D-19. Enlargements were made in the usual manner.
The source of light was a quartz mercury-vapor lamp similar in construction to that described by Allen, Franklin and McDonald (I). A quartz monochromator was used to divide the light spectrum into bands.
Darkening of the nucleus in the photomicrographs is an indication that the nuclear material absorbed light at that wave length. The darkening in the photographic image of the nuclear material by light absorption produces an effect in the pictures resembling the effect obtained by staining of the nuclear material prior to photography with ordinary light.
The photomicrographs (Figs. ra and Ib) show that there was very little absorption of light by the nuclei at the wave lengths 4350 A, 3654 A, and 3022 A.