Abstract
Several workers have found large variations in the size of Trichomonas vaginalis in fresh preparations from vaginal discharges. Powell 1 reported lengths of 10 to 30μ and Wenrich 2 in 2 sets of preparations obtained lengths of 18 to 36 and 12.6 to 27μ. There has been some question concerning the cause of these variations, 1 and it was with the hope of clarifying this situation that this experiment was undertaken.
The materials and culture-methods used in this experiment are the same as those employed by Johnson. 3
T. vaginalis was grown in media at various pH values and the organisms were measured. Observations were made on the living organisms sealed with vaseline under a microslip supported by glass fragments. The organisms were thoroughly distributed throughout the media before samples were taken. Measurements of length and width were made on the first 35 motile organisms encountered in the field. No measurements were taken of the amoeboid forms which are considered degenerative. 2
Two-day cultures—The minimal mean size of the organisms (12.4±O.13μ in length and 9.4±0.11μ. in width) appeared at approximately pH 5.40. The maximal mean size (15 ±0.23ν in length and 11.6±:0.18μ in width) occurred at pH 7.60. Between these extremes there was a progressive although somewhat irregular increase in size with increase in pH. The extreme range was from 6.4 to 24μ in length and from 4.8 to 19.2μ in width.
Four-day cultures—After 4 days the media which exhibited a pH of 6.64 to 5.15 after 2 days had become more acid (pH 6.44 and 4.93), while the less acid media became slightly more alkaline (about 0.1 pH unit).
The minimal mean size of protozoa (11.4±0.12 by 9.0±0.10μ occurred at about pH 5.10 to 5.17.
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