He was sent to Latin America by the physiologist Emil du Bois-Reymond, to study the electric eel (Electrophorus) in the same Llanos region where Humboldt had made his observations;[1][2][3] he took with him a galvanometer and electrodes to measure the fish's electric organ discharge, and used rubber gloves ("Kautschuck-Handschuhen") to enable him to catch the fish without being shocked, to the surprise of the local people.
He published his research on the fish, including his discovery of what is now called Sachs' organ, in 1877.
[3] He observed that electric eels gather in groups as water levels fall in the dry season.
He tried to bring six of the fish home on his return journey across the Atlantic, but one died on the voyage back to the port of Bremen, and the rest were harmed on the train journey to Berlin.
[7] Sachs died aged 25 in 1878, not long after returning to Europe, in an accident on Monte Cevedale, Italy.