The effect of some factors on the cell volume of rumen ciliates.

The effect of diluting rumen samples with water and that of formol fixation, on the volume of ophryoscolecid rumen ciliates, was studied. The dilution with water caused within 2 hrs. the ciliates to swell to an average of 60 % (15.4–107.3). During 15 days of formol fixation, the shrinkage was on an average (0.0–19.8) of the original volume. When the thickness of the cells was conceived equal to the width, volumes 35–77 % too large were obtained. The influence of these sources of error on calculations of rumen fauna volumes is discussed.