256 Miss M. P. FitzGerald. Further Observations on the 



oxygen pressure was lower than it otherwise would have been. In general I 

 was not conscious of being at a higher altitude than usual, but signs of being 

 at a physiological disadvantage, due to the low alveolar oxygen pressure, were 

 manifested by the constant feeling of great fatigue and, except during the 

 stay at 4250 feet, when work was in part lessened, by poor and unrefreshing 

 sleep.* 



From Highlands the journey was made via Lake Toxaway (seven hours' 

 drive and thence by rail) to Waynesville (altitude 2645 feet), one night 

 being spent on the way at Asheville (altitude 2210 feet). Four days were 

 spent at Waynesville (2645 feet). Stormy weather prevailed. The mean 

 alveolar C0 2 pressure was found to be 34 - 6 mm. of mercury with a barometric 

 pressure of 689 mm. of mercury (corrected barometric pressure 694 mm. 

 C0 2 pressure 34 - 9 mm. of mercury). At Asheville (altitude 2210 feet), where 

 a week was spent after leaving Waynesville, the mean C0 2 pressure in the 

 alveolar air was found also to be within the variation of normal sea-level 

 values, i.e. 34 - 4 mm. of mercury (barometric pressure 708 mm. of mercury). 



The return to sea-level (New York) was made direct from Asheville, a 

 journey of 22 hours and involving a change of altitude of slightly over two 

 thousand feet. Fourteen hours after arrival, the alveolar C0 2 pressure was 

 found to be 33 - l (barometric pressure 766 mm. of mercury), a slightly lower 

 value than usual. On the third day at sea-level the C0 2 pressure was 

 34*0 mm. of mercury. The values obtained during the subsequent three 

 weeks varied from 33 - 2 mm. of mercury to 35*6 mm. of mercury, the normal 

 mean value obtained for New York being 34 - l mm. (mean barometric 

 pressure 759 mm. of mercury). 



Thus at altitudes ranging from 4000 feet to 2000 feet, and at barometric 

 pressures ranging from 663 to 708 mm. of mercury, there appears to be no 

 respiratory reaction in M. P. F. G-. Entirely different behaviour of the 

 respiratory centre was therefore met with below 4000 and above 5000 feet, 

 for in the latter experience (5000-14,000 feet),f although the response of the 

 respiratory centre to want of oxygen was slow, it was nevertheless apparent. 

 From the present series of experiments, and in spite of a stay of eight weeks 

 at 3850 feet, the alveolar C0 2 pressure remained at sea-level value (34 mm. 

 of mercury) at barometric pressures ranging from 759 to 663 mm. of mercury. 



The sea-level value of 34 mm. of mercury falls within the lower limits of 



* In spite of this, however, there was a general improvement in condition as evidenced 

 by increase in bodily weight. Excellent food was provided at the sanatorium, and the 

 daily consumption of food was greater than usuaL It must be borne in mind that 

 fatigue was easily produced since I had been weakened during the previous winter by a 

 chronic Staphylococcus infection. 



t Ibid., p. 367. 



