Theories and Experiments 453 



In fact, speaking of the inspirations of oxygen which had formerly 

 been attempted, they protest against any comparison between the 

 use of this gas and that of compressed air: 



Certainly it is a very different thing to breath pure oxygen, or 

 even oxygenated air, and to breathe air which is merely compressed, 

 without any quantitative modification of its elements, air in which the 

 oxygen is still diluted with nitrogen in the natural proportions. 

 (P. 269.) 



The lengthy note which A. Guerard 14 placed after the impor- 

 tant memoir of Pol and Watelle in the Annales d'Hygiene is only a 

 compilation. It contains nothing new, either from the point of view 

 of phenomena observed or from the point of view of physiological 

 explanations. Only its author stresses, more than anyone had done 

 up to that time, the enormous changes which the increase of pres- 

 sure made in the weight supported by the body. He drew up a 

 detailed table of them, from which, as a curiosity, we extract the 

 following figures: 



At 1 atmosphere the weight supported varies from 15,500 to 20,600 kg 

 At iy 2 atmosphere the weight supported varies from 23,250 to 30,400 kg 

 At 2 atmospheres the weight supported varies from 31,000 to 41,200 kg 

 At 3 atmosphere the weight supported varies from 46,500 to 60,800 kg 

 At 4 atmospheres the weight supported varies from 62,000 to 82,400 kg 

 At 5 atmospheres the weight supported varies from 77,500 to 103,000 kg 

 At 6 atmosphere the weight supported varies from 93,000 to 123,60ff kg 



And he assumed that there were terrible extra weights, since 

 at 5 atmospheres they would vary from 77,500 to 100,000 kilograms! 



Guerard supposes besides that, under the influence of the pres- 

 sure, the oxygen and the nitrogen are dissolved in the blood in 

 greater quantity, and that the result is an increase of interstitial 

 combustions, and consequent emaciation. 



As to the muscular pains, he considers them as being of a rheu- 

 matic nature, and due to the chill which accompanies the decom- 

 pression. 



Then, admitting as general the greater facility of movement 

 which Pol and Mathieu had thought they noted in some of the 

 workmen in compressed air, he says: 



It might be that the influence exerted on walking by the atmos- 

 pheric pressure would be magnified by the increase of this pressure. 



For the rest, he accepts the conclusions of Pol and Watelle and 

 those of Pravaz. 



With Dr. Milliet, 15 we return to observations of a purely medical 

 nature. In the opinion of this physician, the action of compressed 



