Decreased Pressure 961 



more prolonged inspirations that the lung makes up for this deficit, but 

 by more frequent respiratory movements. At Davos, where I observed 

 myself carefully for several days, I noted 18.2 respiratory movements 

 per minute, while at Paris I have only 16.6. (P. 12.) 



As first sign of improvement in the thoracic symptoms of con- 

 sumption, we observe at Davos an increase of respiratory capacity, 

 measured by aid of the spirometer, an instrument used at present in 

 this station (P. 13.) 



On March 22, 1874, Croce-Spinelli and Sivel made their first 

 flight at great height, in which, encouraged by the result of trials 

 made in our cylinders, they took along bags of oxygen, so as to 

 overcome the effects of the decompression by breathing this gas. 

 The Polar Star, in which they made the ascension, a balloon of 

 2800 cubic meters, took them in two hours to a height of 7300 

 meters. I quote here the part of their account 1J which applies to 

 our subject: 



We felt in our flight impressions similar to those which we had 

 experienced in the decompression bells of M. Bert, in which several 

 days before the ascension we were taken down to a pressure of 304 

 millimeters. However, in the basket, in which we reached 300 milli- 

 meters, the discomfort was much keener than in the bell, which should 

 be attributed to the harder work done, to the great drop in temper- 

 ature, and to the duration of our stay in the upper strata. While in 

 the basket we underwent cold of — 22 to — 24 degrees, we had a con- 

 stant temperature of +13 during the decompression on earth; further- 

 more, the sojourn in the bell lasted only an hour, which is almost the 

 duration of that part of lofty ascensions which is above 7000 meters, 

 whereas we remained in the air 2 hours and 40 minutes, and one hour 

 and 45 minutes above 5000 meters. Moreover, in the bell, the pure 

 oxygen which we were breathing caused dizzy spells like those of 

 drunkenness, whereas on the contrary we were very comfortable with 

 the two mixtures, one of 40% oxygen and 60% nitrogen, and the other 

 of 70% oxygen and 30% nitrogen, which M. Bert had furnished us 

 for our ascent. 



We began to breathe the 40% mixture at 3600 meters, and con- 

 tinued to 6000 meters; we resorted to that of 70% for the great 

 heights, because the less rich was insufficient, particularly for M. 

 Croce-Spinelli. In the most rarefied regions, we both had to leave in 

 our mouths the rubber tubes connected with the gas bags. We 

 breathed thus from time to time, taking care to grip between our 

 teeth the elastic tube when we felt better. When M. Sivel threw out 

 ballast, which prevented him from breathing gas, the 15 kilogram 

 bags seemed to him to weigh 100. 



For M. Croce-Spinelli, of lymphatico-nervous temperament, the 

 effects were quite different than for M. Sivel, a very vigorous man, of 

 sanguine temperament. When the former was no longer breathing 

 oxygen, he was obliged to sit down on a bag of ballast and make his 

 observations, motionless in that position. During the absorption of 



