AIR AND LIFE. 189 



environmental conditions other than those of altitude which may have 

 produced the observed effects. In order to meet this argument M. Paul 

 Begnard has devised an experiment which affords a very precise and 

 unassailable demonstration. In this experiment the only difference is 

 a difference in pressure. If the increase in the respiratory capacity of 

 the blood that occurs in consequence of life at high altitudes is occa- 

 sioned solely by diminution of pressure, it is clear that such diminution 

 ought to produce the same effect at any altitude whatever. So M. Paul 

 Kegnard took two guinea pigs belonging to the same litter, placed one 

 in a bell jar, where a special apparatus not only provided the necessary 

 decrease of pressure (by exhausting the atmosphere to the requisite 

 degree), but effected the necessary ventilation, while the other lived in 

 the same laboratory under normal pressure. The decrease of pressure 

 in the bell jar and the density of the atmosphere corresponded exactly 

 to those which obtain at Santa Fe de Bogota, at 3,000 meters above 

 sea level. Both animals were killed after a mouth, and the result was 

 that the blood of the guinea pig under decreased pressure absorbed 

 21 cubic centimeters of oxygen (per 100 cubic centimeters blood), while 

 that of the other animal living under normal pressure absorbed only 

 14 to 15 cubic centimeters of oxygen at the most. The fact is quite 

 clear; the experiment most convincing. By some means not yet ascer- 

 tained the blood of creatures living at high altitudes, and able to with- 

 stand the first unpleasant sensations, acquires the power of accumulat- 

 ing a large proportion of oxygen, and thus their systems are enabled 

 to resist that incipient asphyxia which is the result of a smaller pro- 

 portion of oxygen in the atmosphere. 



This is an important point, from the practical side. It explains the 

 beneficent influence of high-level stations (such as St. Moriz, in Switz- 

 erland) upon amende or tuberculous patients. It shows that in cases 

 where the organism is weakened and physiologically impoverished, and 

 particularly where the blood has lost some of its vitality, the patient 

 will be benefited by living for some time in mountain resorts, even 

 at comparatively high altitudes, his blood will acquire new life, and 

 become more apt to fulfill its functions, owing to the increase of 

 respiratory capacity that results from decrease of pressure. 



It is evident, however, that the patient should begin with moderate 

 altitudes, 1,500 meters, for instance; with altitudes which do not over- 

 task the system, which do not palpably increase the physiological ten- 

 dency toward asphyxia, and one should not forget that decrease of 

 pressure which, if moderate, is beneficent, becomes invariably fatal if 

 it exceeds certain limits. Man does not seem to be adapted to live per- 

 manently at altitudes over 4,000 or 5,000 meters, and if other animals 

 are able to do so, it is quite certain that even for these also there is a 

 limit upon which they can not trespass without dangerous results. The 

 differences are only of degree, and upon the whole they are of small 

 amount. 



