Packard has made a strong argument in regard to the value and importance of the mineral elements contained in plant life, in connection with the disturbances in these same elements which has been observed in connection with cancer, as we have already seen. He recalls that modern chemistry teaches that the inorganic principles of the vegetable kingdom are absolutely necessary to the highest degree and type of animal tissue and health, and resistance to disease. Plant life is the connection between the minerals and salts of the earth and animal life, but in the manufacture or refinement, and cooking, of products of the vegetable kingdom, many of them are largely demineralized; this especially illustrated in the case of fine white wheat flour, rice, potatoes (in peeling and cooking), etc. So that while animals get plenty of mineral matter from plants and the earth, man gets but little, and while the herbivorous animals are rarely affected with cancer, civilized man is succumbing to it more and more. It is stated that among savage tribes, who are practically free from cancer, the water in which vegetables are cooked is also consumed as food, thus securing all the salts. The same idea has been popularly presented to the public in a startling manner by McCann in a book which, with a great deal of verbiage contains a large amount of valuable information concerning nutrition, and its disturbance by erroneous, or worse, preparation and administration of food. Possibly there are other dietary elements which may play some part in the causation of cancer, but the demonstrated facts in regard to them are so few and uncertain that they need not detain us here, although it is certainly desirable to investigate any that seem to have reasonable support.