578 METABOLISM 



the same, but that of women is 6.8 per cent lower than that of men. The 

 basal metabolism of a group of men and women between the ages of forty 

 and fifty was 4.3 per cent below the average for the larger group between 

 the ages of twenty and fifty; and that of a group between fifty and sixty 

 years was 11.3 per cent lower. 



Influence of Diseases 



The measurements have been made by the direct method which has just 

 been described, but since the much simpler indirect method (page 589) 

 yields comparable results, it is being adopted for clinical purposes. These 

 results were obtained by making parallel determinations of energy out- 

 put by both methods, in disease as well as in health. Some of the ob- 

 servations that have been made on the energy output in various diseases 

 are as follows: In very severe cases of exophthalmic goiter, heat produc- 

 tion may be increased from 50 to 75 per cent over the normal. The 

 warmth of the skin and the sweating, which are prominent symptoms 

 of this disease, are therefore accounted for by the increased elimina- 

 tion of heat, and it is considered possible that the other symptoms 

 would be caused in any normal individual were his metabolism 

 maintained for months or years at the high level which it occupies in 

 goiter. In the opposite condition of myxedema, the energy output is 

 markedly reduced, but rises slowly during treatment with thyroid extract, 

 or much more rapidly with the very active thyroid hormone recently iso- 

 lated by Kendall (page 798). In diabetes it has often been thought that 

 the rapid emaciation and loss of strength were dependent upon an excit( 

 state of metabolism, or a useless burning up of the energy material. Al- 

 though an increase could not be shown when the surface area was used as a 

 basis for calculation (Du Bois) the group method shows an increased 

 energy metabolism in many cases of diabetes amounting sometimes to 

 12 per cent (Benedict). In uncompensated cases of cardiorenal dis- 

 'ease, there is increased energy output. In pernicious anemia metabolism 

 is normal, although in severe cases there may be an increased demand for 

 oxygen. 



Even at the risk of repetition, it is important to point out that in all 

 these diseases the energy output is the same whether measured directly or 

 by the indirect method about to be described. 



The value of following the basal metabolism in the therapy of exoph- 

 thalmic goiter has been demonstrated in recent work by Means and 

 Aub, who have followed the metabolism and clinical condition of a series 

 of cases over a period of several years. They found in the majority of 

 cases that the results with the x-ray treatment are as good as those se- 

 cured by surgical methods. The basal metabolism shows a rapid pre- 



