(2d ed.), by Sherman.

[6] "The Basis of Nutrition," by Graham Lusk.

[7] "Food Products," by Henry Sherman.

[8] Abstracts made from thirteen papers from the Laboratory of
Physiological Chemistry, Jefferson Medical College, Philadelphia;
published in the "American Journal of Physiology and Science," by
Minna C. Denton. U.S. Department of Agriculture.

[9] "Chemistry of Food and Nutrition" (revised), p. 333, by Henry
Sherman.

[10] "Chemistry of Food and Nutrition" (revised edition), by Sherman.

[11] "The Vitamine Manual," p. 64, by Walter Eddy

[12] Courtesy of Dr. E. V. McCollum.

[13] Milk from cows whose diet has been deficient in vitamines shows a
like deficiency in vitamine content--the same is true of mother's
milk.

[14] "The Vitamine Manual," p. 64, by Walter H. Eddy.

CHAPTER II

THE FUEL VALUE OF FOOD

Science has proved that the human body is composed of certain chemical
elements and that food materials are combinations of like elements; it
has likewise proved that the body will utilize her own structure for
fuel to carry on the work of her various functions unless material is
supplied for this purpose from an outside source, namely, food, which
in chemical composition so closely resembles that of the human body.

~Amount and Type of Food.~--The next point of investigation would
logically be the amount and kind of food necessary to best accomplish
this purpose. To be able to do this it was necessary to have some
standard unit by which to measure the amount of heat each food was
capable of producing when burned outside the body, after which it was
more or less simple to calculate the heat production of each of the
food combinations within the organism. An apparatus known as the "Bomb
Calorimeter"[15] was devised by Berthelot, and adapted for the
examination of food materials by Atwater and Blakesley. The food
material to be tested was placed within the bomb, which was charged
with a known amount of pure oxygen. The bomb was then sealed and
immersed in a weighed amount of pure water, into which a very delicate
thermometer was inserted. The food within the bomb was ignited by
means of an electric fuse, and the heat given off by the burning of
the material was communicated to the surrounding water and was
registered upon the thermometer. It was evident that some definite
name had to be devised by which these heat units might be known. Hence
the name "~calorie~," which represents _the am