350 Historical 



experiments of M. Fernet (page 249) , carried out meanwhile, ap- 

 peared to justify them completely, seeming to show that the vol- 

 umes of oxygen absorbed by the blood are almost independent of 

 the barometric pressure. 



Everyone yielded then to these conclusions supported by ex- 

 periments which give no opening for any objection of a purely 

 physico-chemical type. 



M. Jourdanet alone (page 258) did not declare himself con- 

 vinced. He remarked shrewdly that no matter how great was the 

 affinity of the corpuscles for oxygen in the respiratory act, there 

 was no doubt that in an air with low oxygen content, the solu- 

 bility of this gas in the blood would be less. It cannot be other 

 wise in rarefied air, and the blood there must take up a lessened, 

 and possibly an insufficient, quantity of oxygen. Join to that the 

 decrease due to the cause of which de Saussure had spoken and 

 to which M. Jourdanet attributes considerable importance, and you 

 will become convinced, he thought, that on the mountains the 

 blood has a lower oxygen content than at sea level; and this de- 

 crease in oxygen, although the number of blood corpuscles remains 

 the same, produces the same dangerous effects as a decrease in 

 the number of these corpuscles. Anoxemia is the pathological 

 counterpart of anemia; thence comes this notable statement: "An 

 ascent above 3000 meters is equivalent to a barometric disoxyge- 

 nation of the blood, as a bleeding is a corpuscular disoxygenation" 

 (page 261). When the symptoms are carried to the extreme, as 

 happens on lofty mountains, the violent symptoms which we have 

 described are the result of the irrigation of the organs by a blood 

 containing too little oxygen, incapable of. stimulating and nourish- 

 ing them. At lower altitudes, as on the Mexican plateau, the dif- 

 ference in the oxygen content is not great enough to bring on dis- 

 turbances serious enough to attract attention, in the usual condi- 

 tions of life. But if some illness is contracted, it will immediately 

 take on a character so peculiar that an experienced physician will 

 at once recognize in his patient a real anemic. This is the general 

 thesis which M. Jourdanet has ardently sustained since 1861; he 

 has supported it in the successive works, which we have already 

 reviewed, with an astonishing number of personal observations 

 and quotations in agreement with them. 



To be sure, more or less definite statements had been made 

 before his time, as we have seen, about insufficient absorption of 

 oxygen, and even about blood incompletely oxygenated; but no 

 one had connected the two causes which may produce a low oxy- 

 gen content in the blood, or measured their importance, or shown 



