The authors describe the results of investigations on the influence of phenol derivatives on the eggs of Ascaris lumbricoides. A destructive effect on these eggs showed: 2,4-dichlorophenol, 2,5-dichlorophenol, 2, 4, 5-trichlorophenol and 2,2-dihydroxy-3,3' -5,5' -6,6' chlorodiphenylomethane.
The authors give an account of the results of their investigations on the helminthofauna of the rats Rattus norvegicus, caught in the Warsaw area and suburbs. 150 rats were examined and 6 species of parasites found. The authors confirm after Obitz (1933) a permanent occurrence of Trichosomoides crassicauda in Poland and emphasize an increase in infections of rats with endoparasites in the Warsaw area, in the period 1933-1958.
The effect of antiseptics from the aryl group of aromatic hydroxy acids on Ascaris lumbricoides and A. suum eggs was investigated by the method of direct contact (at 26°C). The preparations applied showed no destructive effect on the eggs of the above mentioned worms.