dear," began Uncle William, looking slightly worried,
"there's my eggs that I _always_ have, you know."

"For heaven's sake, Billy, what _have_ you got hold of now?" demanded
Bertram, with just a touch of irritation.

Billy laughed merrily.

"Well, I suppose I didn't sound very logical," she admitted. "But the
book--you just wait. It's in the kitchen. I'm going to get it." And with
laughing eagerness she ran from the room.

In a moment she had returned, book in hand.

"Now listen. _This_ is the real thing--not my garbled inaccuracies. 'The
food which we eat serves three purposes: it builds the body substance,
bone, muscle, etc., it produces heat in the body, and it generates vital
energy. Nitrogen in different chemical combinations contributes largely
to the manufacture of body substances; the fats produce heat; and the
starches and sugars go to make the vital energy. The nitrogenous food
elements we call proteins; the fats and oils, fats; and the starches and
sugars (because of the predominance of carbon), we call carbohydrates.
Now in selecting the diet for the day you should take care to choose
those foods which give the proteins, fats, and carbohydrates in just the
right proportion.'"

"Oh, Billy!" groaned Bertram.

"But it's so, Bertram," maintained Billy, anxiously. "And it's every bit
here. I don't have to guess at it at all. They even give the quantities
of calories of energy required for different sized men. I'm going
to measure you both to-morrow; and you must be weighed, too," she
continued, ignoring the sniffs of remonstrance from her two listeners.
"Then I'll know just how many calories to give each of you. They say a
man of average size and weight, and sedentary occupation, should have
at least 2,000 calories--and some authorities say 3,000--in this
proportion: proteins, 300 calories, fats, 350 calories, carbohydrates,
1,350 calories. But you both are taller than five feet five inches, and
I should think you weighed more than 145 pounds; so I can't tell just
yet how many calories you will need."

"How many we will need, indeed!" ejaculated Bertram.

"But, my dear, you know I have to have my eggs," began Uncle William
again, in a worried voice.

"Of course you do, dear; and you shall have them," soothed Billy,
brightly. "It's only that I'll have to be careful and balance up the
other things for the day accordingly. Don't you see? Now listen. We'll
see what eggs are." She turned the leaves rapid