In a study of 3,000 mastectomies, Salomon compared X-rays of the beasts (mammograms) to the actual removed tissue, paying close attention to microcalcifications. In doing so he was able to establish the difference in X-ray images between cancerous and non-cancerous tumors of the breast, founding the study of mammography. "Salomon's mammographs provided substantial information about the spread of tumors and their borders.^[5] In the midst of the study, Salomon also discovered that there are multiple types of breast cancer" (Wikipedia).