[Effect of a varying concentration of boron on the tempo of Paramecium caudatum multiplication depending on the temperature of the medium].

The rate of multiplication of Paramecium caudatum was studied using individual cultures with media containing 0.001, 0.005, 0.008 and 0.01% borate, resp. At room temperature (20--21 degrees C) with two first concentrations of boron, the ciliates multiply normally over 4 months often surpassing the multiplication rate of the control line. With the increase of boron concentration up to 0.008%, the division rate in paramecia decreases significantly, reaching the control rate only by the end of the 3rd month. At high temperature (26--27 degrees) with 0.001 and 0.005% of boron in the media, P. caudatum was also seen to multiply normally. At lower temperature (15--17 degrees) all the test concentrations of borate used decreased the rate of division, and the higher the concentration of boron the more pronounced was the depressing effect.