Studies in carotenogenesis. 19. A survey of the polyenes in a number of ripe berries.

(31 %), m-nitrophenol (9%), p-nitrophenol (9%), m-aminophenol (4%), o-aminophenol (3 %), 4nitrocatechol (0.7 %), aniline (033%) and o-nitrophenol (0.1%). Two new metabolites, nitroquinol (0.1%) and p-nitrophenylmercapturic acid (0.3%), were found in the urine. 4. The denitration products, phenol, catechol, L-phenylmercapturic acid, and trans-tran8-muconic acid, did not occur in the urine. 5. Nitrosobenzene, azoxybenzene, azobenzene and benzidine, the presence of which would have substantiated the occurrence of nitrosobenzene and phenylhydroxylamine as intermediates in the formation of p-aminophenol, were not detected in the urine. 6. The total excretion of radioactivity in the expired air, urine and faeces accounts for nearly 70% of the dose of nitrobenzene in 4-5 days after dosing. The remainder is present in the tissues and is eliminated slowly as metabolites in the urine, which is still radioactive 10 days after dosing, and probably also as carbon dioxide. 7. Two days after dosing, about 54% of the administered radioactivity was found in the tissues, particularly in the fat and the intestinal tract. Unchanged nitrobenzene was present in the tissues of this animal. Eight days after dosing, in another experiment, 8% of the radioactivity was found in the tissues, the fat being the most active. No free nitrobenzene was detected in this animal. 8. The faeces contain about 9% of the administered radioactivity, of which about 6% is present as p-aminophenol. 9. These experiments account for 85-90% of the administered nitrobenzene.