Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: they have nothing to do with the formation of the growth. These bodies in most cases are probably natural products of the growth or of the degeneration of the cells themselves or of their nuclei. There have been no organisms found that have been accepted by pathologists in general as the cause of cancer. The various bodies that have been reported as living organisms and the probable cause of cancer have been subsequently proved to be something else. Recently, Rous has discovered a filterable agent which causes a spindle-cell sarcoma in chickens. This at least suggests that there is a definite virus for this particular tumor. It is possible that it may be produced by a microorganism. The absence of microscopic and laboratory proof of the parasitic nature of cancer has forced the believers in this theory to clinical experience for evidence to prove the theory. This evidence has been insufficient. It is based on the possible infectiousness of cancer, as shown by cases of cancer a deux, cancer houses, streets, districts, etc. As stated in the section on infectiousness of cancer, all these conditions can be explained in other ways and there is little or no evidence that cancer is contagious. It is possible that in the future, a parasite or living organism will be found to be the cause of cancer. The discovery of the cause of syphilis, and the resemblance of cancer in some respects to this disease, has made this seem more probable to some observers. Up to the present time, however, that cancer is caused by a microorganism is a theory only and not an established fact. CAUSE OF CANCER. The real cause of cancer is still one of the unsolved problems of scientific medicine. The great frequency of the disease, effecting people of all classes in all civilized countries has...