While on the topic of diet, a word should be said about cooking. In a previous chapter the advantage of good cookery as an aid to digestion was emphasized. We would add here merely the comment that in defending the ancestral diet we do not intend to imply that their cookery was always what it should have been. Over most of America there has prevailed from pioneer days a habit of frying food in preference to other means of cooking it. Our hardy pioneer ancestors throve on fried meats; an outdoor life of muscular toil makes almost any kind of cookery both acceptable and digestible. As labor-saving machines tend more and more to diminish the amount of muscular labor that most of us do, we find it harder and harder to maintain good digestion on fried foods. The objection to frying is simple; fats are the hardest of all foods to digest and fried foods are smeared all over with fat. It is only logical to expect fried foods to be harder to digest than other kinds; it is undeniable that the flavor of many fried foods is so agreeable that we would be unwilling to omit them from the diet altogether. What is realty objectionable is the practice of smearing all the food with fat in the process of cooking it. We have finished what we have to say about the use of food for the repair of bodily wastage. While we are on the topic, a few words about the use of food in growth will come in well, since the growth process is closely related to the process of tissue repair. The chief difference between them is that the process of growth comes to an end in all but a few of our body tissues as soon as we become adults. The tissues which go on growing are the layers of the skin just under the surface, the reproductive tissues, and the blood-corpuscle-forming tissues. Connective tissue has the power to grow at any time during life, although it does not actually keep on growing as does the skin. Whenever an injury is suffered which actually destroys muscular tissue or the deep layers of the skin, there is no growth of new tissue to take the place of either. Repair is made by a growth of connective tissue to fill up the space. The result is the formation of a scar. If the edges of the injury can be brought together skillfully enough, the outer layers of the skin which do have the power of growth may bridge across the space so that no scar will result.