1. Chemical studies on the levels of adrenalin-cortical material in the blood show marked differences in the cases who recover from insulin shock therapy as compared with those who fail to recover.2. The curves of recovered cases are characterized by a rising residual A-C level and a stability in the amounts present even under the stress of hypoglycemic coma and electric shock.3. Failures are characterized by a persistently low A-C value with great susceptibility to change when shocks are applied.4. The significance of these findings for an understanding of schizophrenia is discussed.Abstract Teaser