The metabolic behaviour of 7 women suffering from cancer of the breast and of 3 normal women has been investigated with reference to the excretion of corticoids (TTC chromogens) and oestrogens, put in evidence by the conditions of the testosterone test. In 4 patients the increase of the level of corticoids was striking. Different possibilities of reactions and relations to the survival time are discussed. The remaining 3 patients and the normal women showed no appreciable alteration in the excretion of corticoids. With another composition of the group of persons we observed two different behaviours regarding the excretion of oestrogens. An increase was seen in 2 normal women and in 5 patients. The excretion of oestrogens showed an only slight alteration in the remaining 3 cases. The 4 modes of reaction seen in two groups of steroids enabled the relative classification of the patients with cancer of the breast. Apart of these same types of reaction other ones were seen in normal women.