This discovery respecting the important place which milk is capable of filling in the solution of the great and pressing problem of human nutrition is a highly important one, and its value has led to very active efforts on the part of the U. S. Department of Agriculture to enlarge the dairy interests and increase the milk production of the country as one of the best means of food economy which could be adopted. But even this is not a complete solution of the difficulty, for the keeping of milch cattle involves still a very large waste of food material, five pounds being consumed by the cow for each pound produced. The evident reason for this is the fact that the cow requires the large part of the foods she eats for her own use in maintaining heat production, supplying energy for exercise, supporting the work of the heart, lungs, digestive organs, etc. The food value of the milk produced represents simply what is left over after the cow has made use of what she needs for herself.
There can be no doubt that as meat production diminishes, as it is certain to do, milk production will likewise decrease. There is even at the present time a notable shortage of dairy products, and the average per capita production will undoubtedly continue to decrease for the same causes which inevitably lead to a lessened meat production. Some other source for the complete proteins needed to supplement the incomplete proteins of cereals and roots must be provided. Fortunately, Nature has supplied us with this all-essential foodstuff in that choicest of all our products, the nut. This is a vitally important fact which sometime will save the race from protein starvation.
A study of the relative protein content of nuts, milk, and meat shows that, pound for pound, the almond, beech nut and walnut contain on an average as much protein as does meat and five times as much as is found in milk, and protein which from rat feeding experiments appears to be of equal value. The chestnut, the chinquapin, the filbert, the hickory, pecan and pine nut contain on an average as much protein as is found in fish, while the butternut, the peanut and the pignolia contain twice as much or 50 per cent more than is found in the best of meat.