I 



1920] FOODS — HUMAN NUTRITION. 565 



scvt'ral successive sojourns in liiKli altitudes under conditions as nearly uni- 

 form as possil)lo. Tlie three lii^li aititaide stations were Leadville, Colo., 8,100, 

 tlie sliore of Fallen Leaf Lake, of the Sierra Nevada Mountains, 1,9(X), and 

 Tike's Peak, 3,100 meters above sea level. The diets in all of the experiments 

 were uniform, and the composition was determined by the composite sample 

 method. 



I. Effect of hiijJi (iltitiidcn on pul>ie, hodij trnipvrdtuvc, blood pressure, respira- 

 tion rate, output of urine, and loss of energy in feces (pp. 71-8G). — The results 

 of this study may be summarized as follows : 



At elevations below 3,000 meters the quickening effect of the altitude on the 

 pulse rate was inconstant, while above 3,000 meters the pulse rate was accel- 

 erated, particularly at first. After descending to low altitudes subnormal pulse 

 rates were observed. 



The body temperature was not appreciably affected at altitudes up to 3,000 

 meters, while above that altitude the temperature was increa.sed. Mountain 

 sickness was not accompanied by rise of temperature.. 



The systolic blood pressure was increa.sed at altitudes of from 3,100 to 4,300 

 meters. 



The volume of urine was decreased in the two to four first days at high ele- 

 vations, but later an increase in volume took place. The assimilation of energy 

 was not altered at high elevations. 



II. Effect of high altitudes on protein metabolism (pp. 87-104). — In four ex- 

 periments in high altitudes on a uniform low protein diet great variations were 

 observed in the protein metabolism. At an altitude of 1,900 meters a slight 

 retention of nitrogen was observed in the subject who had not previously lived 

 at high elevations, but no appreciable effect on the protein metabolism was noted 

 in the other subject. In the first period at 3,100 meters, the nitrogen and 

 sulphur balances were negative, while the phosphorus balance was positive. In 

 the second period, at the same elevation, an initial increase of the protein cata- 

 bolism was followed by a tendency to retain nitrogen and sulphur. The phos- 

 phorus balance was close to ofiuilibriura. At an elevation of 4,300 meters the 

 nitrogen and phosphorus balances were close to equilibrium, the sulphijir bal- 

 ance slightly negative. The calcium balance was negative in all but the period 

 at 4,300 meters, when it was slightly positive. 



III. Effect of high altitudes on iron metabolism, (pp. 105-112). — "On a uni- 

 form diet, with a normal iron content, the iron balance did not alter at an ele- 

 vation of 3,100 meters, although the erythropoetic organs were stimulated to 

 greater activity. On a uniform diet, rich in organic iron compouTids, the 

 retention of iron at an elevation of 1,900 meters did not excee<l the iron reten- 

 tion observed in low altitude.' On a uniform diet of normal iron content to 

 which iron acetate was added a great elimination of iron occurred at eleva- 

 tions of 3,100 and 4,300 meters. As the number of erythrocytes simultaneously 

 decreased, it is suggested that the heavy output of iron w-as caused by the 

 hemolysis of red blood corpuscles." 



IV. Effect of high altitudes on the carbon dioxid content and on the hgdrogen- 

 ion concentration of the blood (pp. 113-120). — "The indirect determination by 

 other observers of the CO2 content of the blood in high altitudes from observa- 

 tion on the alveolar COj tension, showing a proportional decrca.se with decreas- 

 ing atmospheric pressure, have been confirmed at elevations of 3,100 meters 

 and 4,3(K) meters by direct determinations of the COi content of the bloods 



"Alterations of the hydrogen-ion concentration of the blood have been ob- 

 served in high altitudes. A slight acidosis was found when an apparently suc- 

 cessful acclimatization was going on. A slight alkalosis was present in a case 

 of mountain sickness. 



