Improvements to the counting of microscopic body such as the red or white blood

摘要

398,164. Gauging-apparatus. HILGER, Ltd., A., TWYMAN, F., and FOLLETT, D. H., 98, King's Road, Camden Road, London. Feb. 5, 1932, No. 3503. [Class 106 (ii).] Microscopic particles such as blood corpuscles are enumerated by passing light through a specimen and measuring the light diffracted by the particles. The size of the particles is estimated by causing the light, after it has passed through the specimen, to form an image, and measuring the size of the coloured diffraction rings produced. The apparatus is contained within a casing to which light is admitted through a variable aperture 1 from a lamp mounted on the outside of the casing. The light is reflected by a prism 2 to a lens 3 forming an image on a black spot on a lens 8. Immediately below the lens 3 is a unit 4 comprising a diffusing plate and an iris diaphragm, this unit being mounted on a pivot 5 so that it can be removed from the light path. The blood film is supported by a stage 6 above a rotatable platform 7 having a clear aperture 14 and a screen 16 bearing scales for measuring the diffraction rings. To estimate the size of the particles the platform 7 is turned to bring the screen 16 below the slide 6 and the size of the diffraction rings is measured by observation through an aperture 18.