NO. I AIR AND TUBERCULOSIS — HINSDALE 65 



the increment at altitudes. In agreement with most observers the adjustment 

 of the blood to the new atmospheric conditions in ascending to higher levels 

 occurs promptly ; there is a rapid increase in the factors involved at the 

 start followed by a more gradual continuation of the effect ; but on returning 

 toward the sea-level the blood does not resume its " low altitude " composi- 

 tion so promptly. There may be a prolonged delay in the adjustment 

 and return to normal figures.* 



Cohnheim ' regards evaporation as the cause of the concentration 

 of blood under these conditions and that this is not due to a lack of 

 oxygen. These studies in hematology have an important bearing on 

 the course of tuberculosis at high altitudes, and constitute a very 

 live question at the present day. 



Professor Cohnheim and Dr. Weber' have recently reported the results 

 of examination of the blood of twenty-three persons who have been engaged 

 for long periods in the operations of the railway ascending the Jungfrau peak 

 in the Alps. Most of them spent considerable portions of their time at alti- 

 tudes from 2,300 meters (7,546 feet, Eigergletscher Station) upward to 

 3,450 meters (11,319 feet, Jungfraujoch Station). The importance of these 

 observations lies in the fact that they furnish data regarding persons who 

 have had prolonged experience in the higher altitudes so that the incidents 

 of temporary residence and change of scene may be regarded as equalized or 

 eliminated. They supplement the earlier records from the South American 

 plateaus by results obtained with approved and up-to-date procedures. The 

 new statistics agree in exhibiting values both for red blood-corpuscles and 

 hemoglobin distinctly higher than the " normals " of sea level. Cohnheim 

 maintains that the high figures thus obtained on a large scale from subjects 

 accustomed to live at high atmospheric levels leave no alternative except to 

 assume a new formation of corpuscles under such conditions. Where contrary 

 conclusions have been reached — and there are many such — it is not unlikely 

 that the period of residence was too brief to permit the stimulating effects 

 of altitude to manifest themselves in any conspicuous way. 



The renewed assumption of an increased functioning of the hemopoietic 

 organs at high altitudes has further been supported by observations conducted 

 on Monte Rosa in the Alps relating to the regeneration of blood after severe 

 anemias. In the international laboratory built on the Col d'Olen at an altitude 

 of 2,900 meters (9,515 feet) and dedicated to the memory of Angelo Mosso, 

 Laquer ' has found that dogs deprived by hemorrhage of half their blood- 

 supply regenerate it in about sixteen days. Under precisely comparable 

 experimental conditions twenty-seven days are required at lower levels for the 

 restoration of the same blood loss. Laquer believes that the lower partial 

 pressure of the oxygen is the effective stimulating factor in this more pro- 



* Editorial in Journ. Amer. Med. Ass., Nov. i, 1913, q. v. 



^ For a recent review of this subject see Cohnheim, O. : Physiologic des 

 Alpinismus, II. Ergebn. d. Physiol., 1912, xii, 628; also Anglo-American 

 Expedition to Pike's Peak, Journal Amer. Med. Ass., Aug. 10, 1912, p. 449. 



'Cohnheim, O., and Weber: Die Blutbildung im Hochgebirge, Deutsch, 

 Arch. f. klin. Med., 1913, ex, 225. 



