The author believes that infection is the cause of cancer, and this book, as the title indicates, is an explanation of why he holds this theory. More specifically, he attempts to identify the infecting agent as "the mold fungus, an organism capable of modifying its form and properties when subjected to a change in environment." He considers that the pleomorphism of this organism acting in different tissues is responsible for the development of "carcinoma, sarcoma, pernicious anemia, leukemia, Paget's Disease, rodent ulcer... cancer granuloma, Hodgkin's Disease, and mycosis fungoides." He believes that heredity plays an important role and that, in addition to the "mold or fungus," a devitalizing agent to reduce cellular resistance to invasion is also essential.
Among the studies being pursued to determine the cause or causes of cancer, investigations on micro-organisms have long occupied an important position. Whether or not human cancers have infectious agents as necessary