A Reducing Substance in Tumours

Abstract

THE indications previously obtained¹ that the high reducing capacity of tumours in our dichloro-phenolindophenol test is due principally to a substance other than vitamin C have now been confirmed. In determinations of vitamin C content, by the histological tooth protection method, groups of guinea pigs were given 5 gm. each per day of freshly excised Jensen rat sarcoma (kindly provided by Mrs. Barbara Holmes). The various control groups received 0, 1, 2, 3 and 4 c.c. of orange juice, and 5 c.c. of orange juice plus 5 gm. of sarcoma. The degrees of protection afforded were found to be 1–2 for the sarcoma, 0, 1–2, 2–3, 3, 3–4 respectively for the orange juice controls, and 3–4 for orange juice plus sarcoma (4 = complete protection). It follows that 5 gm. of the tumour is equivalent in vitamin C content to no more than about 1 c.c. of orange juice.