Theories and Experiments 307 



be established, for instance in the diving bell, comparable, in this 

 respect, to the basket of the aerostat. 



The fatal disaster which has just startled the world of science and 

 the two victims of which were buried this very day urges me to make 

 this suggestion to the Academy, even if it is only a digression useful, 

 perhaps, to the interesting communication of M. Woillez. 



M. Woillez: I cannot give an opinion here on so important a mat- 

 ter; but it seems to me that it is not only a question of respiration; 

 we must particularly take into consideration the decrease in the atmos- 

 pheric pressure for which the oxygen they had taken along could give 

 no help. 



M. Colin: Since the question of the balloon has been brought up, 

 I should like to give my opinion of the causes of the death of the 

 aeronauts. Certainly these causes are multiple, especially those con- 

 nected with the decrease of pressure; some are already indicated by 

 the conditions in which the aeronauts were. 



Two had lunched and they are dead; the other was fasting and he 

 survived. The escape of gases into the digestive tract of the first two 

 might have played a great part in the progress of asphyxia. We know 

 that this escape is very great in ruminants following the eating of 

 green fodder, and that it may, at ordinary pressure, produce sudden 

 death by asphyxia by immobilizing the diaphragm. No doubt this 

 escape is more limited in man: but it increases as a result of illness 

 and indigestion, and then, since the expansion of the gases increases 

 as the pressure decreases, the diaphragm is soon vigorously crowded 

 upward; its movements become very limited and finally become impos- 

 sible. We know that at a certain moment, when the traveller is climb- 

 ing high mountains, he is seized by lassitude, his arms and legs are 

 worn out; the muscles, irrigated by a blood which is imperfectly 

 oxygenated, lose their energy. The diaphragm shares in this fatigue, 

 and finally becomes inert, especially if it is crowded back by the 

 expansion of the gases of the stomach. 



I know very well that aeronauts need to fortify themselves against 

 becoming chilled, and that fasting does not warm them, but they can 

 arrange their meals in such a way as to complete digestion before 

 starting, and replace fermentable food by respiratory food, by liquids 

 which stimulate and develop heat. 



Observations made on the victims and the survivor show clearly 

 the chief cause of the symptoms. This cause is not, whatever M. Bert 

 may say, the lack of oxygen, for in the experiments the animals do 

 not die with the proportion of this gas which may be in the air at 

 7000 or 8000 meters. It is the decrease of pressure, as M. Woillez has 

 just said, which produces the serious symptoms, the hemorrhages in 

 the respiratory passages, the circulatory disturbances, etc. 



M. Blot: M. Colin's last words seem to me to contradict what he 

 said at the beginning. So he explains death first by the compression 

 of the diaphragm and the lungs under the influence of the expansion 

 of the intestinal gases, and finally attributes it to the decrease in 

 pressure. 



As to the comparison between the herbivores and man, it seems to 

 me very debatable. 



