The foregoing experiments may be sufficient to establish the existence in malignant tissues of a substance which, when injected into animals, brings about a marked depression of the liver catalase activity in these animals. Positive results were obtained in all the malignant tissues examined, carcinoma was well as sarcoma, primary as well as metastatic growths, and surgical as well as autopsy materials.<br>The entire results may conveniently be tabulated together for ready inspection. (Table 3).<br>It may be noted in these results that there are some variation in the activity of different samples of the alcoholic precipitates. Some samples were highly active in 50mg amounts; with others the amount had to be increased to 100mg in order to produce the same degree of effect; while there were a few exceptional samples which did not give very clean-cut effect even in 100mg doses. There was a single sample (Gastric cancer ID) which definitely failed to affect the liver catalase activity. As to this particular sample we already stated that an active fraction was recovered from it by re-extracting it with water, however. See descriptions under the head of Gastric Carcinoma.<br>Whether or not the apparent difference in the activity of various samples is due to the actual difference in the toxohormone contents amongs different individual tumors cannot now be determined, although such may proved to be the case. It must not be lost sight of, however, that slight differences in the processes of preparing the fraction may have an appreciable effect on the quality of the final precipitate.<br>Difference in the activity of various samples of the precipitate cannot be correlated to the kinds of tumor tissue from which the samples were derived, it being impossible to say that any one type of malignant growth yields more potent precipitate than others. It seems reasonable to expect that a relation between the histological character and toxohormone content of cancer tissue may exist, but this aspect of the subject must be left for future investigation.