The Bacteriology of Tuberculosis

a statistical basis. These latter studies have indicated that daughters and sisters of females with breast cancer had a significantly greater chance of developing cancer than persons in various control groups used in these studies. Unfortunately faulty planning and idea execution existed in so far as the control groups were concerned and it was on this basis that a study was started at the Dight Institute for Human Genetics of the University of Minnesota. This study was planned to overcome the faults of previous similar attempts to ascertain the role of heredity in the cancer problem. The present volume is a detailed report of this study in which 621 breast cancer patients were carefully interviewed from multiple viewpoints with emphasis on the choice of original patients and the completeness of information. There is value of course in the scientific application of such fact finding, but perhaps more important are the clinical applications. The authors state that the study was designed primarily to answer the question: "Do relatives of breast cancer patients have an increased risk of developing cancer?" The query is answered from a voluminous mass of statistical material all of which is presented in the report. The final impression of the authors is that 7.4 per cent of the study group sisters would develop breast cancer before they die as compared with 4.2 per cent of the control sisters. Further, it was demonstrated that once a cancer has developed in one breast the risk of one developing in the other breast is about three times that for other women of the same age. The authors conclude that "it is very likely that genetic factors are involved in the etiology of breast cancer, but they are either so common in the population or depend so much upon environmental factors for expression that it is difficult to demonstrate their effect." At the end of the book the authors suggest several areas which bear further investigation including hormonal studies of cancer patients and their families and a study of mechanisms of gene action at a biochemical level. This is a fine study which should be read by all workers dealing with the cancer problem. This book represents a very complete and comprehensive reference text for academic and clinical bacteriologists. Dr. Darzins has masterfully documented the important techniques used in the study of the tubercle bacillus and has integrated these descriptions with supporting …