The initial experiments in the study of variations in basal metabolism were carried out at Wesleyan University, Middletown, Connecticut, with several subjects who seemed to show potentialities for low metabolism. The first study was that of a man who had but one lung,1 the assumption being made that with diminished lung area there might be distinctly different metabolic activity. The results of this experiment, although perhaps somewhat open to debate when judged by modern technique and compared with modern data, indicated no striking change in the level of metabolism.

From time to time during the past two decades certain individuals, particularly those who have given more than ordinary attention to their dietetic habits, have come forward with the contention that they were able to subsist upon considerably less food than is required by the normal individual. The first one studied was the case of the late Mr. Horace Fletcher. Mr. Fletcher had interested himself in sociological and economic problems for a number of years and had brought himself to believe that by means of a peculiar adjustment of diet and particularly a supposedly advantageous method of excessive mastication, he could subsist upon materially lower amounts of food and with a much lower metabolism than normal individuals. His contention was seemingly supported by the observations of Professor Chittenden,2 of Yale University. While the observations on Mr. Fletcher dealt primarily with the total nitrogen metabolism, Professor Chittenden, in commenting upon the excessive muscular work done, makes the following statement regarding the energy transformation:

"Yet the work was done without apparently drawing upon any reserve the body may have possessed. The diet, small though it was, and with only half the accepted requirement in fuel value, still sufficed to furnish the requisite energy. The work was accomplished with perfect ease, without strain, without the usual resultant lameness, without taxing the heart or lungs, and without loss of body-weight. In other words, in Mr. Fletcher's case at least, the body machinery was kept in perfect fitness without the consumption of any such quantities of fuel as has generally been considered necessary."3

In other words, on the low energy intake of approximately 1,700 calories Mr. Fletcher, carrying out the training regime and exercises of the Yale University crew, was able to perform a day's duty of this type with supposedly no draft upon body material.

1 Carpenter and Benedict, Am. Journ. Physiol., 1909, 23, p. 412.

2 Chittenden, Pop. Sci. Monthly, 1903, 63, p. 130; ibid., 1907, 71, p. 536. 3 Chittenden, Pop. Sci. Monthly, 1903, 63, p. 130.

Mr. Fletcher was also studied in 1903 for three successive days inside the respiration calorimeter at Wesleyan University.1 While his daily activities were necessarily somewhat restricted by the confines of the respiration chamber, a careful record of the movements, hours of sleep, etc., and analyses of both intake and output in terms of chemical elements and of heat showed that the energy transformations of Mr. Fletcher were in no wise different from those of normal individuals. With present-day knowledge of the factors influencing metabolism, we may say, however, that probably Mr. Fletcher's age at that time (54 years) must have played a slight r61e. Here again, therefore, the search for a materially lowered metabolism was unavailing.

Another prominent food investigator studied was Dr. J. H. Kellogg, who has given not a little attention to his own diet, and whose interest and activity in dietetic regimes are well known throughout this country. Subsisting upon a vegetarian diet for many years and particularly on a low protein diet, Dr. Kellogg was convinced that he lived upon a very much lower metabolic plane than the normal individual. This was set forth in a letter published by Mr. Fletcher,2 from which one infers that Dr. Kellogg believed he subsisted upon approximately 1,200 calories per day. Dr. Kellogg kindly consented to enter the respiration chamber for an experiment comprising several short periods at Wesleyan University in 1906.3 We were thus able to measure his metabolism when he was asleep, sitting, standing, and walking. From these measurements the probable food requirement was computed. A minimum estimate showed a daily requirement of not less than 2,000 calories. Since the body-weight of Dr. Kellogg was 56.1 kilograms, we thus have a metabolism that is not appreciably lower than that of other individuals, although here again the age factor undoubtedly played some slight role.

Another subject who had given special attention to dietetic matters, Dr. M. Hindhede of Copenhagen, was a visitor at the Nutrition Laboratory for a short time in 1910. Although observations could not be made with him according to the strictest basal requirements, nevertheless the metabolism was determined in two or three respiration calorimeter experiments. Although he had presumably been subsisting for several years upon an extraordinarily low-protein and vegetarian diet, his metabolism as measured was not sufficiently low to indicate that his metabolic level was different from that of normal individuals.4

The experiment made with Mr. Fletcher at Wesleyan University in 1903 was supplemented by an experiment of only 4 periods at the Nutrition Laboratory in 1912. This was carried out under strictly basal conditions, and reported by Benedict, Emmes, Roth, and Smith, in their summary of metabolism measurements for 89 men and 68 women.1 At this time Mr. Fletcher was 63 years old and appreciably over-weight, having a body-weight without clothing of 82.1 kg., with a height of 166 cm. The measurements of the metabolism gave a heat production of 19.7 calories per kilogram of body-weight per 24 hours. This is materially different from the average of 25.5 calories for the whole group of 89 men and, in fact, is lower than that for any other individual in the group. The nearest approach to this value was found with Professor Otto Cohnheim, who visited the Laboratory at about this time. With an age of 36 years, a body-weight of 83 kg., and a height of 169 cm., Professor Cohnheim (in 12 observations on 3 days) gave a heat production of 19.9 calories per kilogram and per 24 hours. Although Professor Cohnheim was much younger than Mr. Fletcher, of a highly nervous temperament in contrast to the phlegmatic temperament of the latter, and also a liberal meat-eater, the differences in age, temperament, and dietetic habits were more than counterbalanced by the decided overweight of the two men. It is evident that this excess body-weight and adipose tissue had an effect upon the heat production per kilogram of body-weight of both men. Nevertheless the fact remains that the value for Mr. Fletcher of 19.7 calories is the absolute minimum for values obtained with 89 men reported in 1914.

1 Benedict and Milner, U. S. Dept. Agr., Office Exp. Sta. Bull. 175, 1907, p. 199. 2 Fletcher, The A. B.-Z. of our own nutrition, New York, 1903, p. xxxiii. 3 Benedict and Carpenter, Carnegie Inst. Wash. Pub. No. 126, 1910, pp. 75 and 96. 4 Benedict and Carpenter, Carnegie Inst. Wash. Pub. No. 261, 1918, pp. 191 and 192.