Piltdown are parts of the same individual.[13] [13] But see foot-note on p. 284. [Illustration: FIG. 29.--Complete Skull and Jaw of Eoanthropus Dawsoni. One-third the natural diameter. The parts indicated by dotted lines are re-constructed. The rest is drawn from the actual bones discovered at Piltdown.] [Illustration: FIG. 30.--The complete Skull and Jaw of a young Chimpanzee. Drawn of one-half the natural diameter in order to compare with Fig. 29, representing the adult skull of Eoanthropus, reduced to about the same size.] CHAPTER XXXI THE SUPPLY OF PURE MILK IT is becoming more and more certain that the character and quality of the actual things--the natural products--which we use as food and accept as "diet" are far more important matters in regard to the preservation of health than had been until recently supposed. There has been a tendency, resulting from some of the well-ascertained chemical necessities of the animal body and the equally well-ascertained chemical composition of different articles of food, to suppose that all that we have to do in regard to diet is to make sure that our food supplies us with so much carbon, hydrogen, nitrogen, and oxygen, with small quantities of phosphates, sulphates, and chlorides of potassium, sodium, calcium (lime), and iron, in a "digestible" form, in order to replace those chemical elements as their combinations are used up and thrown off as waste by our bodies. The general notions current are little more exact than this. It is recognized, it is true, that these elements must be combined in certain forms; that it is necessary to take so much "proteid" (meat, gluten of flour, casein of cheese and milk, albumen of egg), in which nitrogen is a leading component, foods which are called flesh-formers; and, further, that it is necessary to take others which supply carbon and hydrogen but have no nitrogen, namely, the hydro-carbons--fat, butter, and oil--and the carbo-hydrates--sugar and starch--foods which serve as mere fuel or heat-and-force givers. The late proprietor of "Truth," Mr. Henry Labouchere, once said to me that the doctors ought to provide us with a sausage containing in their simplest form the necessary proportions of proteid and of heat-giver (fat and sugar), and that we should abandon all "sit-down" meals, pulling the necessary sausage out of our pockets without any fuss or interruption to our occupation, and eating a couple of inches or so, three or four times a day! Experimental feeding of animals (in menageries, etc.), and even of men (in prison, on the march, and on ships), has sometimes taken very nearly as simple a form as this.