The presence of ergothioneine in the central nervous system and its probable identity with the cerebellar factor.

1. Ergothioneine has been detected and quantitatively estimated in the brains of mice, rats, guinea-pigs, rabbits, cats and sheep. It is present in the cerebellum in amounts ranging from about 3.0 mug/g in the cat to 10 mug/g in the guinea-pig. Amounts in the cerebral hemispheres are much smaller, ranging from < 0.1 mug/g in the cat to 1.6 mug/g in the guinea-pig.2. Large amounts of ergothioneine (about 30 mug/g) were found in the optic nerves of the rabbit. None was detected in the dorsal columns of the spinal cord of the same species.3. Ergothioneine has an excitatory action on the electrical activity of the cerebellum of the decerebrate rabbit and the excitatory actions of cerebellar extracts on this preparation are completely accounted for by their contained ergothioneine.4. It is concluded that the cerebellar factor of Crossland & Mitchell (1956) is identical with ergothioneine.