Figure 93. 



Paul Bert's apparatus for showing the effects of varying 

 low pressures of oxygen and CO2. The tap B is connected with 

 an air pump, and D with a bag of oxygen or nitrogen, while C 

 connects with a mercury manometer. 



Figure 94. 



Paul Bert's twin steel chamber for studying in man the 

 effects of very low atmospheric pressures with respiration of 

 oxygen. 



