When we inquire into the cause of the systemic disturbance which tends to such faulty metabolism that the nutrition of cellular structures is deranged, even to the degree of taking on malignant action, we find many possible elements, more or less connected with what is known as modern civilization, to which we have time to but briefly allude. Williams has shown pretty clearly that wealth, with its tendency to luxury and idleness, greatly increased the proclivity to cancer: not only is this observed in different countries, but in certain cities the difference is very striking between the cancer mortality in sections which are occupied by the rich and well-to-do, and those in which the poorer classes are herded. Also in England it was found in one decennium that cancer mortality was more than twice as great among the well-to-do men, having no specific occupation, as among occupied males in general, the ratio being 96 to 44. Change in the mode of life, and sudden changes of environment have also been found to have a great effect in the production of cancer, as has already been mentioned in another lecture. Finally, for our time does not permit a fuller discussion, nervous conditions unquestionably can and very often do exert a profound influence on the secretion of the various organs of the body, and can so disturb digestion, metabolism, and nutrition that the most varied results may follow, to which the names of different diseases are given; so that nerve strain, more or less incident to modern life, must be accredited with a certain share of influence in the production of cancer. The part which imperfect and deficient intestinal and urinary excretion play in inducing or perpetuating the disease will be treated of in later lectures. In our next lecture we will consider certain matters relating to the medical treatment of cancer, but from long experience and study I am firmly convinced that such measures are of relatively little service unless coupled with a rigid care of the diet and hygiene. As Bell remarks, “Cancer is essentially a disease supervening upon a persistent neglect of hygienic laws.” It is a disease of sub-oxidation, and all the hygienic elements of importance in tuberculosis are equally necessary in cancer; fresh air and sunlight with, as far as possible, an ideal regulation of life in all its aspects, are indispensable.