When we consider the small share which nitrogen plays in the composition of the human frame, as shown in the table presented, only three per cent., it is easy to see how an excess of nitrogenous food must necessarily either pass off unassimilated or undergo imperfect metabolism, and so derange the general metabolism; and this is found to be the case in many conditions of disease, and, as has been shown, in cancer. Chalmers Watson and others have shown in a most remarkable manner, by animal experiments, that an excessive meat diet alters very materially the microscopic structure of very many organs and portions of the body. Beneke, who is often quoted, was one of the first to seriously consider the actual diet beneficial in cancer, his observations dating back to 1875 upon material in the service of Esmarck and Oldehop, who treated patients according to his plan. While the diet he gives is not wholly vegetarian, he limits the nitrogenous intake very greatly, and reported some very favorable results, with the complete disappearance of some malignant new formations. Referring now to the data presented in the second lecture, in regard to the frequency and geographical distribution of cancer, we can understand better, on scientific grounds some of the reasons why cancer is so steadily increasing in civilized communities, and why in some sections of the earth it is less common, while certain aborigines have seemed to be almost immune. We found that in England the per capita consumption of meat was 130 pounds per year, and that it had doubled during the past fifty years, while during the same period cancer had increased _four fold_; but in Ireland, where the meat consumption was estimated in 1895 at only 40 pounds per capita, or less than one-third that in England, the cancer death rate is very much lower, not much over one-half. We found that in Italy, where the per capita consumption of meat was the smallest of any European country the cancer death rate was almost the lowest. Also that in certain other countries, where vegetarianism was the rule, cancer was very infrequent, while among certain aborigines the disease was practically unknown; but we found also that in both the latter classes of individuals cancer has slowly increased, in proportion as the inhabitants of different sections had come under the influence of modern civilization, and adopted the dietary and other habits of foreigners. In the United States cancer has certainly increased very greatly during the last fifty years, and statistics were presented showing that in seven of the largest cities, during the past five years, the number of cancer deaths had augmented between seven and eight per cent. It is known that the consumption of meat here has increased steadily, until in a communication from the Bureau of Agriculture in Washington we learn that it had recently reached the enormous amount of 172 pounds per capita yearly, much more than in England.