Method for determining the action of active ingredients on nematodes and other organisms in aqueous tests, comprising the following steps: a) filling at least one well of a cell culture plate with nematodes and an active ingredient; b) arranging the cell culture plate in a device comprising: - a holder for the cell culture plate, said cell culture plate having a bottom side, a top side and also side walls extending between bottom side and top side, and the wells of the cell culture plate being closed by a well-cover, - a camera which is used to record images of the cell culture plate, - a lighting mechanism having at least a first light source which illuminates the cell culture plate; there being arranged between the first light source and a first side wall of the cell culture plate in the installed state a first optical unit which directs the light of the first light source through the first side wall in the direction of the bottom side of the cell culture plate; c) creating multiple images of the cell culture plate that follow one another chronologically; d) binarizing the created images depending on an illumination of the cell culture plate; e) determining a first measurement curve based on the well for a first series of images, said first series having a base image and multiple follow-up images, with each follow-up image being compared to the base image in a difference method and a number of difference pixels being determined; f) determining at least a second measurement curve based on the well for a second series of images, and, for the second series, using a follow-up image of the first series as base image and at least one further follow-up image of the first series as a follow-up image of the second series; g) determining an averaged curve on the basis of the first measurement curve and of the at least second measurement curve. a) filling at least one well of a cell culture plate with nematodes and an active ingredient; b) arranging the cell culture plate in a device comprising: - a holder for the cell culture plate, said cell culture plate having a bottom side, a top side and also side walls extending between bottom side and top side, and the wells of the cell culture plate being closed by a well-cover, - a camera which is used to record images of the cell culture plate, - a lighting mechanism having at least a first light source which illuminates the cell culture plate; there being arranged between the first light source and a first side wall of the cell culture plate in the installed state a first optical unit which directs the light of the first light source through the first side wall in the direction of the bottom side of the cell culture plate; - a holder for the cell culture plate, said cell culture plate having a bottom side, a top side and also side walls extending between bottom side and top side, and the wells of the cell culture plate being closed by a well-cover, - a camera which is used to record images of the cell culture plate, - a lighting mechanism having at least a first light source which illuminates the cell culture plate; there being arranged between the first light source and a first side wall of the cell culture plate in the installed state a first optical unit which directs the light of the first light source through the first side wall in the direction of the bottom side of the cell culture plate; c) creating multiple images of the cell culture plate that follow one another chronologically; d) binarizing the created images depending on an illumination of the cell culture plate; e) determining a first measurement curve based on the well for a first series of images, said first series having a base image and multiple follow-up images, with each follow-up image being compared to the base image in a difference method and a number of difference pixels being determined; f) determining at least a second measurement curve based on the well for a second series of images, and, for the second series, using a follow-up image of the first series as base image and at least one further follow-up image of the first series as a follow-up image of the second series; g) determining an averaged curve on the basis of the first measurement curve and of the at least second measurement curve.