Johann Ludwig Wilhelm Thudichum (1829-1901) was a German physician and biochemist. Thudichum was a pioneer in the field of neurochemistry, and a founder of "brain chemistry". He performed chemical analyses of over one thousand human and animal brains, and specialized in pathological chemistry. He is credited with the identification and characterization of numerous compounds of the brain, including cephalin, sphingomyelin, galactose, lactic acid and sphingosine.