Transportation of expedition equipment on a donkey harnessed to a cart. Members of the expedition float on the lake on a boat, catch the larvae of anopheles mosquitoes with a net for research. Oil water in the lake: a man with a hand pump sprays oil on the water. Camping laboratory of the expedition on the shore of the lake. A member of the expedition examines the larvae of anopheles mosquito through a microscope. Treatment of water in the lake with Parisian greens (salts of arsenic acids).