438 



BLOOD AND LYMPH. 



altitudes may be compensated by an increased amount of hemo- 

 globin, and subsequently Viault* demonstrated that hving for a 

 short time at very high altitudes (4000 meters) causes a marked in- 

 crease in the number of red corpuscles — an increase, for instance, 

 from 5,000,000 per c.mm. to 7,000,000 or even 8,000,000. This fact 

 Haemoglobin- 



I" 800 



180 



Altiiiide 

 350 300 inFt. 



24.000 

 23i000 



IftOOO 

 18.000 

 17.000 

 16,000 

 15.000 



7,000 

 6,000 

 5,000 

 4,000 

 3.000 

 2,000 

 1,000 



800 750 700 650 600 550 500 450 400 350 300 



Almospheric pressure in mm of mercury. 



Fig. 185 a. — To show the relationship between altitude and the percentage of hemoglobin 

 in the blood. Figures along the bottom give the atmospheric pressure; along the ordinate to 

 the right the altitude in feet, and along the ordinate to the left the percentage of hemoglobin. — 



(Fitzgerald.) 



has since been investigated with great care by a large number of 

 observers and under a great variety of conditions. The observa- 

 tion has been abundantly confirmed. A graphic illustration of the 

 relationship between altitude and the number of red corpuscles or 

 * Viault, "Comptes rendus de Tacademie des sciences," 1890 and 1891. 



