The elements of the science of nutrition / by Graham Lusk.

  • Graham Lusk
Date:
1917
Catalogue details

Licence: In copyright

Credit: The elements of the science of nutrition / by Graham Lusk. Source: Wellcome Collection.

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    summer clothing than a temperature of 2° would have during perfect atmospheric quiet. In all the experiments the smallest amount of carbon dioxid is eliminated between 30° and 40°. The above experiments were performed on a thin man, and it will be noticed that there was no rise in his metabolism at a temperature of between 350 and 40°. Rubner explains this as due to the suffi- ciency of the evaporation of perspiration on the surface for the cooling of the organism. A fat man, however, with a thick, ill-conducting layer of adipose tissue is not so immune to the effect of high temperatures upon his metabolism. This is especially pronounced in a damp climate. Thus Rubner1 obtains the following results from a fat man wearing clothes: INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE METABOLISM OF A FAT MAN Humidity 30 Per Cent. Humidity 60 Per Cent. Temperature CO2 in Grams per Hour Grams H2O Evapo- rated per Hour CO2 in Grams per Hour Grams H2O Evapo- rated per Hour 20° 33-7 56 30- 7 17 28-30° 36.9* 134 44 - 51 170+ 3i g- sweat. 36-370 42.6f 204 + 14 g- sweat. 46.7§ 186 + 255 g. sweat. * Body temperature rose o.i°. f Body temperature rose 0.40. f Body temperature rose o.o°. § Body temperature rose 0.90. The fact that in the experiment where there was 30 per cent, humidity the metabolism largely increased at 36° to 370 without concomitant rise in body temperature leads Rubner to theorize that there must have been an overheating of the cells where the metabo- lism was progressing, even though this might not have been determinable by the clinical thermometer. It appears that on a hot, humid day the metabolism of a fat indi- vidual may be 50 per cent, higher than on a day of moderate tem- perature and the same humidity. The whole of the body heat is lost through the evaporation of water which is here hindered by the 1 Rubner, M.: “Energiegesetze,” 1902, pp. 208, 232. 11