Carl Sachs (19 September 1853–18 August 1878) was a German zoologist, known for his discovery of what is now called Sachs' organ in the

electric eel The electric eels are a genus, ''Electrophorus'', of neotropical freshwater fish from South America in the family Gymnotidae. They are known for their ability to stun their prey by generating electricity, delivering shocks at up to 860 volt ...

Biography

Carl Sachs was born in

Neisse The Lusatian Neisse (german: Lausitzer Neiße; pl, Nysa Łużycka; cs, Lužická Nisa; Upper Sorbian: ''Łužiska Nysa''; Lower Sorbian: ''Łužyska Nysa''), or Western Neisse, is a river in northern Central Europe.Emil du Bois-Reymond Emil Heinrich du Bois-Reymond (7 November 181826 December 1896) was a German physician and physiologist, the co-discoverer of nerve action potential, and the developer of experimental electrophysiology. Life Du Bois-Reymond was born in Berlin a ...

, to study the

(''Electrophorus'') in the same Llanos region where Humboldt had made his observations; he took with him a

galvanometer A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvan ...

and electrodes to measure the fish's electric organ discharge, and used rubber gloves ("") 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. While in the Llanos, he used giant toads instead of the frogs that du Bois-Reymond's laboratory normally employed to detect electrical activity from electric fish. Sachs studied the electric eel's seeming immunity to its own shocks, and to electricity applied to it. He found that electric eel muscles, when removed from the fish, twitched in the usual way in response to an electric shock. He demonstrated that a discharge could be triggered by stimulating the nerve to the electric organs; and that such a discharge could be blocked with the

arrow poison Arrow poisons are used to poison arrow heads or darts for the purposes of hunting and warfare. They have been used by indigenous peoples worldwide and are still in use in areas of South America, Africa and Asia. Notable examples are the poisons se ...

curare Curare ( /kʊˈrɑːri/ or /kjʊˈrɑːri/; ''koo-rah-ree'' or ''kyoo-rah-ree'') is a common name for various alkaloid arrow poisons originating from plant extracts. Used as a paralyzing agent by indigenous peoples in Central and South ...

. He observed that electric eels gather in groups as water levels fall in the dry season. Abstracts in English. File:Sachs on Electric Eel 1877.png, Sachs' illustration of what is now called Sachs's organ (in black at 6) in the

, with electric organ discharge patterns (4, 5, 8), 1877 File:Sachs sections and anatomy of electric eel 1881.jpg, Sections and anatomy of electric eel, published posthumously by Sach's employer,

Emil du Bois-Reymond Emil Heinrich du Bois-Reymond (7 November 181826 December 1896) was a German physician and physiologist, the co-discoverer of nerve action potential, and the developer of experimental electrophysiology. Life Du Bois-Reymond was born in Berlin a ...

, in 1881 Sachs produced an accurate anatomical description of "Sachs's organ", the smallest of the electric eel's three

electric organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the pump organ, harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has sinc ...

s. 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 A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ha ...

, and the rest were harmed on the train journey to Berlin. Accordingly his researches on these specimens were limited to anatomy. The organ is now known to produce a low-voltage discharge used in

electrolocation Electroreception and electrogenesis are the closely-related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes to stu ...

. He was the first person to write descriptions of the electric organs of the weakly electric ''

Gymnotus ''Gymnotus'' is a genus of Neotropical freshwater fish in the family Gymnotidae found widely in South America, Central America and southern Mexico (36th parallel south to 18th parallel north). The greatest species richness is found in the Amaz ...

'' fishes, members of the same family as the electric eel. Sachs died aged 25 in 1878, not long after returning to Europe, in an accident on

Monte Cevedale Monte Cevedale is a mountain at the border of the Lombardy and Trentino-Alto Adige/Südtirol regions in Italy. The southern summit (3769 m) is the highest mountain of Trentino province, while three provinces, Sondrio, South Tyrol it, Prov ...

, Italy.

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Biography

Works

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Further reading