The same may be said in regard to so-called “cancer houses” concerning which there are still occasional references. A careful investigation of these houses has commonly found them to be old, moldy, damp, badly ventilated, and otherwise unsanitary; also that such old houses are commonly tenanted by old people in succession, so that there are more at a cancer age to be affected. With our present knowledge of the causes which lead up to cancer we cannot but conclude, therefore, that the occurrence of the disease in groups, with some apparent connection, has been only the result of all living under the same conditions of ill health, including wrong diet, etc.; for we know that cancer is not contagious or infectious, and there is no other reasonable explanation which can be sustained. FOOD AND MODE OF LIFE.—In my former lectures I presented very fully the evidence that cancer was certainly a disease of civilization, its frequency and mortality advancing steadily in proportion as various tribes or peoples, previously exempt, have come more or less under its influence and adopted its manners and customs. When we speak, therefore, of the influence of food in the production of cancer it must be understood that it is not claimed that the diseased process depends wholly and exclusively on the character of the food, including drink, taken. In my former lectures I tried to show that cancer was the result of a deranged nutrition, and we know that one of the greatest elements in inducing this latter is erroneous metabolism, depending again on the diet, to a very great extent. In a later lecture I shall hope to develop this subject further, and indicate more completely than on the previous occasion, the elements of causation and the measures which can be successful in overcoming the disease. In order to understand rightly the rôle which diet may have in the production of cancer I may have to briefly repeat, more or less, some of the matters brought forward in my lectures two years ago, and shall treat of the correction of diet in a later lecture. We understand, of course, that the body is a vast laboratory, wherein, by exceedingly complicated processes, material from the outside world is appropriated to the needs of the economy, and after its use is cast out in very different and elementary forms. To effect the various changes necessary in this material we have a very considerable number of what are called organs of secretion and excretion, whose functions are combined and correlated in a marvelous manner, which is even yet very imperfectly understood.