[17] “On one occasion, when living for five days entirely upon oranges, our temperature was lessened, still we felt a pleasant glow throughout the system; but to other individuals we felt cold; animal heat is therefore only _relative_. We further found that only three or four hours sleep was required in the twenty-four hours.”
The consensus of modern opinion, however, seems to be against any such supposition. Chittenden, for example, writes:[18]
“Man lives in an atmosphere of oxygen and nitrogen. He can and does absorb and utilise the free oxygen of the air he breathes; indeed, it is absolutely essential for his existence, but free nitrogen likewise drawn into the lungs at each inspiration is of no avail for the needs of the body.”
As, however, all bodies contain more or less nitrogen in excess, there would be no need to call upon the air for its supply. It would be interesting to note the effects in cases of nitrogen starvation; but the simple fact that animals _do die_ when sufficient nitrogen is subtracted from their food, would seem to indicate that but little nitrogen, if any, can be extracted from the air, even under these circumstances.
After the above lengthy argument, which endeavours to show that sufficient proteid can be supplied the body from vegetable foods, it is somewhat amusing to find that, as a matter of fact, _far too much proteid_ has invariably been eaten by practically all civilised peoples—and that so far from there being any danger of nitrogen starvation, or lack of sufficient proteid, the danger is all the other way, and four-fifths of all the maladies from which mankind suffers are due to the very fact that an excess of proteid has been eaten! All physiologists agree that the majority of people eat far more, not only of proteid, but of all kinds of food, than is required, according to their tables; and Professor Chittenden has recently shown, as the result of an elaborate series of experiments conducted at Yale, that the average proteid standard set by physiologists, as being necessary for the maintenance of health, is at least _three times too high_! That is, the majority of persons eat considerably more than three times too much proteid! In view of these facts, it is amusing to find so much fear exhibited on all hands in case the proteid supply should not be sufficient in quantity.