there is not sufficient physiologic basis for the assump-
tion that the reaction to the subcutaneous injection of
an active principle of the suprarenal gland is indicative
in clinical medicine of activity of the thyroid gland.
The blood sugar curves as shown in Chart 2, following
the ingestion of 100 gm. of glucose, have not been suf-
ficiently consistent in the different types of cases

Chart 2. The heavy black lines represent the average blood sugar curves following the ingestion of 100 gm. of glucose in patients having various basal metabolic rates; the dotted lines represent the upper and lower limits of each group. A, A' and A", average, upper and lower limits for seven cases with basal metabolic rates between + 40 and +59 per cent.; B, B' and B", six cases between + 11 and +39 per cent.; C, C' and C", ten cases between 40 and 11 per cent.; D, D' and D", sixteen cases above + 60 per cent.; E, E' and E", four cases between 10 and 10 per cent.

studied by us to be of diagnostic value, in spite of the
fact that high and prolonged curves were more fre-
quently found in patients with hyperthyroidism than
in those with hypothyroidism.

CONCLUSIONS

The basal metabolic rate, which is a determination of the heat production in a person under standard conditions, serves as a measurement of the most fundamental process of life itself. Variations of the heat production, and alterations in the body temperature are to be considered rightly a means of fundamental disease classification, and the basal metabolic rate serves as an accurate diagnostic aid in the recognition of the presence or absence of hyperthyroidism.

DETERMINATION OF THE BASAL

METABOLISM

AS A METHOD OF DIAGNOSIS AND AS A GUIDE ΤΟ TREATMENT

JAMES H. MEANS, M.D.

BOSTON

The preceding papers in this symposium have set forth the fundamental principles of the subject in hand, human calorimetry and the basal metabolism of

man.

It will be my purpose to discuss briefly the rôle that calorimetry plays in the clinic of today, the help that calorimetric observations may be expected to give to the clinician both in diagnosis and in therapeutics, and the nature of this help, particularly its extent and its limitations.

The medical profession of this country is indebted to Atwater and to Benedict and to their collaborators for a vast fund of information on the energy metabolism of the normal human being under nearly every conceivable condition. To Benedict also and his collaborators, and to Du Bois and his collaborators, the profession is indebted for the introduction and application of the science of calorimetry to clinical problems. It was with the development of an accurate surface area formula by Eugene H. and Delafield Du Bois1 that clinical calorimetry really became a practical possibility, for it supplied the previously lacking prime requisite, an accurate method of judging of the normality or lack of normality of any given person's metabolism.

Since the advent of this formula, the measurement of the gas exchange and the calculation of the heat

1. Du Bois, Delafield, and Du Bois, E. F.: The Measurement of the Surface Area of Man, Arch. Int. Med. 15: 868 (May) 1915.

production there from, that is to say, indirect calorimetry, has come into increasingly wide use in American clinics, so that today there is a reasonably extensive literature on the subject. The work of Boothby 2 at the Brigham Hospital, Boston, and that with which I have been concerned at the Massachusetts General Hospital, is, I believe, among the earliest of the sort. The latter work was begun in 1914.

The practical application of calorimetry to the clinic has been chiefly in the group of thyroid diseases, and in the following remarks it is with them I shall have chiefly to deal. In other fields, however, certain helpful information has been gathered which I shall discuss briefly a little later on.

Before considering the metabolism in disease, a remark is in order regarding that of the normal person. The physiologist is oftentimes impressed with the unaccountable variations in metabolism of essentally similar normal persons, and for that reason he may feel that the clinician is not justified in assuming a definite standard for. normal metabolism, as is now done. From the physiologist's point of view, he is correct. There are differences in the metabolism of normal persons that are not explainable on the basis of size, weight, form, age or sex. Nevertheless, these variations are slight compared with the gross differences found in disease. The physiologist, accustomed to measuring bodily processes by methods of precision, is impressed by the slight differences which the metabolism of normal subjects shows; the clinician, on the other hand, obliged as he generally is to estimate abnormalities of function by the qualitative information gained by observation at the bedside, is impressed by the constancy of the metabolism of normal persons.

We are familiar with a number of physiologic constants. None of these are constant in an absolute sense.

They are, so to speak, relative constants. From one

2. Boothby, W. M.: Boston M. & S. J. 175: 564 (Oct. 19) 1916. 3. Means, J. H.: Boston M. & S. J. 174: 864 (June 15) 1916.