Have measured the amount of the free amino acids found with in cat's brain that has undergone the repeated Insulin shock, same as often used in curing psychotic patient: and which. according to paper chromatography, proved as follows: 1) As seen from the point of quality, no definite change whatever has happened. 2) Glutamic acid and γ-aminobutyric acid increased in quantity. 3) The ratio γ-aminobutyric acid to glutamic acid showed an increasing tendency.