The twenty-seventh annual report of the Imperial Cancer Research Fund includes a review by Dr. W. Cramer on experimental carcinogenesis, which is proposed to be included in future reports. The report emphasizes the importance of critical commentaries in medical research, particularly in cancer studies. While some criticize cancer research as being unproductive, those with more knowledge recognize that progress requires persistent and extensive work. The Imperial Cancer Research Fund has been conducting such work for twenty-seven years, yielding detailed knowledge about malignant processes. Dr. J. A. Murray highlights observations by Dr. W. Cramer, who suggests that carcinoma development is not solely due to epithelial changes but also involves the removal of inhibitory factors in other tissues. Dr. Ludford's findings on macrophages in tumour-bearing animals may relate to this process. Dr. Crabtree's research confirms Warburg's discovery that cancer cells metabolize sugar into lactic acid more than normal cells, indicating a unique metabolic activity that could aid in studying therapeutic effects. Dr. A. M. Begg studied a filterable tumour in fowls that evolved from a low-malignancy sarcoma to a more malignant, transmissible tumour. Dr. Begg and Dr. Cramer observed that Rous tumours may arise from contamination of laboratory equipment with the Rous sarcoma virus. Their findings suggest that experimental errors may explain some anomalies. Dr. Cramer's review of experimental carcinogenesis provides insights into factors influencing cancer susceptibility. It suggests that individuals vary in their susceptibility to cancer-causing factors, which could explain differences in cancer incidence across countries. This understanding could help explain variations in cancer organ incidence in different populations.The twenty-seventh annual report of the Imperial Cancer Research Fund includes a review by Dr. W. Cramer on experimental carcinogenesis, which is proposed to be included in future reports. The report emphasizes the importance of critical commentaries in medical research, particularly in cancer studies. While some criticize cancer research as being unproductive, those with more knowledge recognize that progress requires persistent and extensive work. The Imperial Cancer Research Fund has been conducting such work for twenty-seven years, yielding detailed knowledge about malignant processes. Dr. J. A. Murray highlights observations by Dr. W. Cramer, who suggests that carcinoma development is not solely due to epithelial changes but also involves the removal of inhibitory factors in other tissues. Dr. Ludford's findings on macrophages in tumour-bearing animals may relate to this process. Dr. Crabtree's research confirms Warburg's discovery that cancer cells metabolize sugar into lactic acid more than normal cells, indicating a unique metabolic activity that could aid in studying therapeutic effects. Dr. A. M. Begg studied a filterable tumour in fowls that evolved from a low-malignancy sarcoma to a more malignant, transmissible tumour. Dr. Begg and Dr. Cramer observed that Rous tumours may arise from contamination of laboratory equipment with the Rous sarcoma virus. Their findings suggest that experimental errors may explain some anomalies. Dr. Cramer's review of experimental carcinogenesis provides insights into factors influencing cancer susceptibility. It suggests that individuals vary in their susceptibility to cancer-causing factors, which could explain differences in cancer incidence across countries. This understanding could help explain variations in cancer organ incidence in different populations.