114 METABOLISM IN SEVERE DIABETES. 



been shown that there is essentially an increased heat production amounting 

 to 10 or 15 per cent. 1 Walking and all muscular activity, also the partaking 

 and the digestion of food, produce an increase in the heat production. The 

 difference in heat production measured on the same subject in the chair calori- 

 meter and in the bed calorimeter is further evidence of the difference in energy 

 output. A careful record of daily routine, muscular activity, exposure to cold, 

 etc., would be necessary for the intelligent computation of the total output of 

 energy from the carbon-dioxide production. It is not outside the range of pos- 

 sibilities that this factor may be of actual benefit in making a tentative compu- 

 tation of the energy requirement in diabetes. That this carbon-dioxide pro- 

 duction can be determined equally as well by the small respiration apparatus 

 as with the large respiration calorimeter has, we think, been fairly demon- 

 strated, and we may conclude from this research that, although calorimetric 

 measurements are highly important and desirable if possible, in severe dia- 

 betes a measurement of the carbon-dioxide production alone, or still better 

 a measure of the oxygen consumption, will give the means for computing 

 with great accuracy the heat production of the individual while lying quietly 

 at rest. 



COMPOSITION OF THE ALVEOLAR AIR OF DIABETICS. 



The carbon-dioxide tension of the alveolar air has come to be regarded as 

 an excellent index of the degree of acidosis by reason of the interesting obser- 

 vations of Beddard, Pembrey and Spriggs 2 and the confirmatory work of 

 Porges, Leimdorfer and Markovici. 3 The presence of acids in the blood causes 

 the respiratory center to respond to a smaller tension of carbon dioxide in the 

 blood ; as the carbon-dioxide tension in the alveolar air bears a direct relation 

 to that in the blood, it is evident that a low alveolar carbon-dioxide tension 

 indicates an acidosis. The alveolar carbon dioxide in normal individuals varies 

 from about 36 to 46 mm. tension of mercury as found by the Haldane method; 4 

 according to results obtained by the Plesch method 5 it is about 10 to 15 per 

 cent higher. 



The best method for determining the alveolar air has not yet been thor- 

 oughly established. Both the Haldane and Plesch methods involve good gas 

 analysis technique and not a little cooperation on the part of the subject. 



Alveolar air determinations were made on three of the subjects, N, Q, and 

 I, and are interesting as showing the presence and degree of acidosis. The 

 observations made with Cases N and Q were by the Haldane method; those 

 with Case I were by the Plesch method. The results obtained with Case N 

 are given in table 128. 



Emmes and Riche, Am. Journ. Physiol., 1911, 17, p. 406. 



2 Beddard, Pembrey and Spriggs, Journ. Physiol., 37, Proceedings Physiol. Soc, 190S, 



p. xxxix. 

 'Porges, Leimdorfer and Markovici, Zeitschr. f. klin. Med., 1911, 73, p. 389. 

 4 Haldane and Priestley, Journ. Physiol., 1905, 32, p. 225. 

 6 Plesch, Zeitschr. f. Exp. Pathol, u. Ther., 1909, 6, p. 380. The Plesch method, in fact, 



gives the carbon-dioxide tension of the venous blood, but we have found that this 



value bears a proportional relation to the alveolar air. 



