First Human Brain Chemicals, 1865–1871

© Science Museum /SSPL

In 1864, the German pharmacologist Oscar Liebrich presented a paper at a meeting in Giessen arguing that brain tissue was composed of a single giant molecule called "protagon." Any simpler lipids that chemists were isolating, Liebrich argued, were simply breakdown products of this primary, high-molecular-weight compound.

The protagon theory had quite an effect on Johann Ludwig Wilhelm Thudichum, a German-born physician and chemist who was working in London under contract to the medical officer of the Privy Council, John Simon. In an 1868 report to Simon, Thudichum wrote that he wanted to explore the theory further: "[Chemists] cannot form any conception of pathological processes of the brain matter before knowing [protagon's] chemical constitution of the whole." But when Thudichum started doing his own experiments on brain chemistry, he quickly became disenchanted with Liebrich's theory.

From 1865 to 1871, Thudichum carefully detailed...

Thudichum isolated, characterized, and often named various brain-derived compounds, including choline platinochloride, lecithin cadmium chloride, phrenosine, and kerasine (as seen above with Thudichum's handwritten labels). "Thudichum's ability to employ this procedure to separate compounds with similar, but slightly different, solubility properties marks him out as a genius of the lipid laboratory," says Theodore Sourkes, a biochemist at McGill University and the author of The Life and Work of J.L.W. Thudichum.

For decades, however, the scientific community largely rejected Thudichum's discoveries. Some accused him of "patent falsification"; others called him a "liar." Only in 1910—almost a decade after his death—was the protagon theory finally laid to rest when three labs in London, Edinburgh, and New York confirmed that protagon was nothing more than a mixture of simpler lipids.

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