Page:Popular Science Monthly Volume 11.djvu/335

Rh But all these symptoms disappeared as by enchantment so soon as I respired some of the oxygen in the bag; returning, however, when I again breathed the air of the cylinder.



Fig. 3 gives the details of one of these experiments. In this figure the times of the different stages of the experiment are given at the foot: just above this is seen the curve which represents the rate of pulsation; and above this another curve, showing the barometric pressure in centimetres: the figures in the left-hand margin represent the changes of pressure and pulsation. It will be seen that, as the pressure is diminished, the pulse is accelerated. Thus, the pressure being 42 centimetres (answering to the elevation of Mont Blanc), the pulse-rate, which at the beginning of the experiment was 60, rose to 84.