The levels of bisulfite binding substances (B.B.S.) in the blood and cerebrospinal fluid were studied in 222 patients with neuropsychiatric and medical disorders and the following conclusions reached:1. The usual range of B.B.S. in the spinal fluid is 1.00-2.25 mgms. per cent, which is usually 35-60 per cent of the amount found in an equivalent blood sample.2. The B.B.S. may or may not be elevated in cases of clinical vitamin B1 deficiency (peripheral neuropathy, beri-beri—possibly Korsakoff and Wernicke's syndromes) but this is also true for conditions in which there is no clinical evidence of vitamin B1 deficiency. Eight cases of peripheral neuropathy in alcoholics were studied. This syndrome in alcoholics is the result of vitamin B1 deficiency.14 Four cases showed an elevated B.B.S. in the blood or cerebrospinal fluid or both, and the other four had normal figures. These variations obtained in both acute and chronic cases. Hence, the B. B. S. in the blood and cerebrospinal fluid cannot be used as an indication of vitamin B1 deficiency.CHART XIII. BEHAVIOR AND CONDUCT DISTURBANCES(TOTAL 93 CASES). [See Figure in Source PDF]3. A comparatively large group of psychiatric disorders, including alcoholic psychoses, schizophrenia, manic-depressive psychoses, miscellaneous psychoses and neuroses and behavior and conduct disorders in children were studied. No constant deviation from the normal was found. Uncontrolled diabetes with marked acetonuria shows a marked elevation in B.B.S.4. Paraldehyde causes an elevation of B.B.S. in the blood for 24 hours. It is suggested that the method employed causes a partial hydrolysis of paraldehyde to acetaldehyde, which latter binds bisulfite and thereby increases the total B.B.S.5. The B.B.S. is not an accurate indication of the pyruvic acid levels in the blood or cerebrospinal fluid. Mention is made of several cases of peripheral neuropathy in alcoholics, with elevated pyruvic acid levels in the body fluids and a normal total B.B.S. Similarly, mention is made of several cases with marked elevation of B.B.S. in the blood and cerebrospinal fluid and a normal pyruvic acid level.6. In cases of elevated B.B.S. in the blood or cerebrospinal fluid, the factors which may contribute to that total must be individually analyzed. Pyruvic acid is only one of these factors.