Photographic scanning and its application in the general physiology of motile cells

Abstract

of selecting and watching one cell at a time, as the human observer must, the emulsion of the photographic scanner watches and impartially records the movements of many or all of the cells in an experimental population simultaneously» By being able to furnish statistical information on the re sponses of entire populations as well as on all of the in dividuals in those populations, the photographic method is superior to any direct observation method. The first use of photography in determining the rate of locomotion of microorganisms appears to have been that of Gomandon (1917, 1919), who employed a time-lapse motion pic ture technique (one frame every six seconds) to study the chemotactie movements of phagocytes in parasitised blood. More recently, Schlenk and Kahmann (1939) and Rlkmenspoel (1957) have used standard-speed cinematographic methods in studies of the locomotion of the sperm cells of the trout and bull, respectively. The measurement of locomotor velocity from motion pic ture records is a tedious process, necessitating, in effect, a reprojection of the entire film record for each cell stud ied. The single-frame time exposure technique makes it pos sible to avoid this difficulty. Wense (1935), in a study of the effects of various neuropharmacological agents on the Paramecium, was apparently the first to make use of this type of photography. In his photographs, made with one-0