Variations in Basal Metabolism and Their Relation to Skin Temperature. ∗

The basal metabolic rates of 47 women 20-29 years old (unselected university students, born and living in a goitrous region and about 50-90% of whom have had adolescent enlargement of the thyroid) have been repeatedly determined by Claire Conklin or myself. None of them had basal metabolic rates above the Aub-Dubois standard and only 5 equal to this standard. The 17 highest averaged 35.87 calories per square meter per hour which is 3% below the Aub-Dubois standard. The remaining 30 averaged 32.15 calories per square meter per hour or 13% below the Aub-Dubois standard. This was true whether the metabolism was calculated from the O₂, CO₂ and urinary N, controlled by an alcohol check, or from the O₂ by means of the Benedict-Roth-Collins method. It was found possible to raise the metabolism of many of the 30 women in the low group to the Aub-Dubois standard in 50 hours by the subcutaneous injection of 5 mg. thyroxine (Hoffman-LaRoche) or ingestion of 25 gm. desiccated thyroid (Eli Lilly). Amenorrhea was more frequent among those with a low B.M.R. and was relieved by thyroid in 2 cases. A short menstrual cycle, 17-26 days, was more frequent in those of lower B.M.R. The menstrual cycle was shortened in one woman by lowering her B.M.R. and lengthened by raising it.

Measurements were made of muscle tone, the psychogalvanic reflex and skin temperature in relation to metabolism. The muscle tone was determined by C. A. McKinley's apparatus. The psychogalvanic reflex was determined by immersing 2 fingers in 2 vessels of salt solution l^ept at constant temperature. It was found that collodion used to define the margin of the zone of electrical contact of skin and salt solution gave rise to errors but that vaseline eliminated these errors.